this is pretty much what i have been doing, but it's gotten extremely frustrating

. my friend is going to allow me to play with her macro lens prior to making any sort of additional purchase, so i'll have a chance to try before i buy... i'm sure i'll post those shots with additional questions when the time comes.
thanks for all your help
Hopefully it's not a Macro lens but just one that has macro features. Otherwise you would be getting 1:1 images of the kids nose.
If you have a Canon 28-105 f/3.5 lens, that should be all you need. It's not the lens or the camera, it's just a matter of getting the fine points and it will all come together.
Lighting is what's at issue. I'm not expert and lighting is always a challenge for any picture.
Like others have pointed out, you need to get more light from the front. Just think of the light coming over your shoulder or somewhere behind you, into the face of the subject, and less from the background. If it's mostly from the side, you'll get heavy shadows and you won't like that either.
With that here's a tip that might be helpful. #1 Find a white handkerchief if you can. (which is a joke, because just finding one is pretty hard now)
So find something white, that will let most of the light through, and drape it over the flash. This will give you the light from the flash, but diffuse it. Heck I've used a cocktail napkin or paper towel, so it's not high tech. Just make sure it's white, because anything else will color the image.
You can make a flash diffuser out of a paper towel and some scotch tape. Then you won't get those dots in the eyes and harsh washed out pictures when you get closer.
That brings up point #2, the color of the walls or ceiling will change the color of a photo, because of the reflected light coming from them. So lets say you take pictures in a room that's salmon colored, everything can have a salmon tint to it, which will drive you crazy!
If you can do anything, like hang a sheet on the wall, or something to get a lighter background, that might help. I can't tell, but it looks like you have tan walls? I suppose you could go the other way and expose for the childs face and have a darker background, who would also make it drop out and be less distraction to your pictures.
#3 (and then I'll shut up)

You really do need to read some books on photography, not even the whole book, just the section on depth of field. Go to the library, it's free. Oh wait, that's the old way. Go on the internet and just search for Depth of Field. Just a couple of articles and you'll have a mental image of what's going to happen, before you take the picture.
Here's the part you want to remember. Focus, when refering to depth of field is not 50/50 front and back. It would be simple and nice if it was, but that's light and optics for you.
Depth of field is roughly 1/3 front and 2/3rds behind. That means 1/3 in front of the point of focus to 2/3rd in back of that exact spot.
If you focus on the shoulders, with a really shallow range, the tip of the nose may be out of focus, but the feet would look fine. Focus on the nose and with that 3.5 lens, the feet may be out. That's why people are saying shut down to at least 5.6 or your depth of field isn't deep enough to have the whole child's head in focus.
For your example, pictures of a very young child, I'll just make up some hypothetical numbers. You need 18 inches of depth. So you should be focused at about 6 inches BEHIND the closest portion of the picture you want in focus, with a depth of field that will extend back 12 inches, that's 18 inches total. Just because something is within the focus range, doesn't mean it's tack sharp in that whole range, just that to the eye, it doesn't appear out of focus. If you only care about the face, then that's fine. Much less depth of field needed.
On your first pictures the sweater is sharp and the childs ears are starting to get lost. You are focused in front of the subject.
Here's a really entertaining experiment, well maybe only for people like me, but I think it's entertaining. :thumbup: Take a yard stick, if you don't have one, take something with writing on it that's large enough to see if it's in focus or not, and a couple of feet long. Put the camera at one end and take a picture along the yardstick.
Do this during daylight, not like I just did. What it shows is the closest point that your camera can focus. I could probably squeek by at 8 inches with this one, maybe 7 1/2? It also demonstrates to some extent, depth of field. If I can re-shoot it tomorrow in the daylight, I'll swap the picture for a better one.
What I'm heading at is if you try to shoot at 110mm you can't get as close, shoot at 28mm and you can be closer and have more depth of field. But it changes the field of view and the way the face will look. Have some fun, try standing close with wide, then further back, take the IDENTICAL shot, same framing, then back a little more, zoom until you get the same image. When you look you will see that even thought everything in the picture is the same, it looks different. In fact look at my avatar.
Your zoom lens at about 50-55mm would be 80-88mm field of view and many portrait photographers through the years have used 85mm lenses.
I understand that you have a potentially moving subject, restricted light, and situational limitations. Maybe if you can diffuse that flash it will help. Do you have a tripod? That would remove one source for movement.
The backlighting on the first picture is interesting. You just need a little more light from the front. Neat part about digital is you can shoot and shoot and shoot and it doesn't cost anything. Experiment. Have Fun!