Funny thing is, I gave you a serious answer within the first 3 posts.
THEN, when you said the settings you shot in, it sounded like you weren't serious b/c whenever a shot comes out like that .... play with other settings to try and make it better. AND you want us to tell us what lense to get. Figure out what you want to shoot, do some research, then come and compare a few lenses and see if anyone has any thoughts or concerns with any of them. Don't just come in and say, "What lense should I buy next ...."
BEST place (one I use) ... go and search flickr groups on certain lenses and read up on them in there, from people with experiences with them and take a look at some of the shots from each.
THE INTERNET: Greatest thing invented (besides toilet paper and cameras), it's got a wealth of information on it (both true and false) ... but it seems to have made people lazier.
Edit: Oh ... can't forget this.
Nikon d5000 and just some everyday family events maybe some new born baby pics or weddings
You don't understand aperture, shutter speed, lens names, etc ... yet you want to shoot weddings.