I did mine 3yrs ago. Depends what kind of projectors you're getting, the ones that i got are from the BMW E46 (cost me $250 inc shipping from USA).
When you're baking the headlights, don't put your headlight in with the oven on. Warm it up about 5-10mins (max temp), then turn it off and put one of your headlights in for about 3-5mins. Once the silicone/glue around the edges have soften, then slowly pry the lens. You need 4 screws to hold each projector in the headlight.
Aligning them is the most annoying. But you should be able to do them over a weekend.
here is my DIY link (really old, but hey at least it gives you an idea): http://www.toyotanation.com/forum/t136335.html
All the best and worst case is for you to get new set of headlights
if you have any further questions, feel free to pm me.