Hi Stephen - welcome to the forum.
In my view, you need a faster lens first. The
$107 50mm f1.8 is a good low light lens, but may be too tight for interiors with a crop sensor camera. My vote would be for the
$199 40mm f2.8. I have shot with this lens and it is a very good value for the money. Alternatively, for a little more, you may want to look at the
$289 35mm f2. A nice prime lens for indoor work.
Next, I would deal with sound. I've gone the
Zoom H1/consumer mic route and I now recommend against it. Too many switches to deal with when you're shooting - and too much hassle when you're trying to match your picture and sound in the edit suite.
Instead of the
$99 Zoom recorder and the
$229 Rode Videomic "Pro" with its unbalanced, consumer 3.5mm output, here is what I recommend:
Sound:
Best value for money pro mic -
Audio Technica AT897, $210
Best value for money shock mount -
Campro Deluxe, $25
WindTech SG-1 foam windscreen for AT897, $31.95
WindTech MM-101 mic muff for AT897, $29.95
Until you can afford a preamp, get yourself a
$17 Hosa MIT-156 XLR to 3.5mm adapter/transformer to plug your mic directly into your camera.
When you can afford a preamp, the best value for money external preamp is the
JuicedLink DT414, $319. This relatively inexpensive little device compares very well with the
$899 professional Sound Devices MixPre-D:
The other area where you can improve the quality of your video is a steady picture. You can get cheap plastic shoulder mounts and tripods, but they will break or wobble or pan jerkily - and you'll end up spending money to replace them. In my view, it is better to start with a metal tripod and rig and be done with it. Here is what I recommend:
Best value for money shoulder rig -
Photography & Cinema, $260
Best value for money fluid head tripod -
Fancier 75mm bowl w crutch style legs, $129
I have the
$140 Ravelli version of this tripod, and it pans and tilts smoothly and is built like a tank. Highly recommended.
Hope that's helpful and good luck with your T3i!
Bill