Wedding photography

So in January my cousin and I will be photographing a wedding for some friends of ours. Neither of us has any experience one the shooting end as far as wedding are concerned, although she does have some experience from what she saw photographers at her wedding doing.

Her equipment:

Canon T3i

Kit 18-55 (terrible I know)

Canon 50mm 1.8

Canon 430 II flash

Separate tripod for off center portrait flash with umbrella diffuser

-she is looking for something with greater range than the 18-55 that has an fstop of at least 2.8. (Input appreciated) to my knowledge her options are basically a 200MM or 145mm prime or a 70-200 2.8. Unfortunately her budget is roughly 600 for that particular lens

My equipment:

Canon 60D

Sigma 17-50mm 2.8

Sigma 50mm 1.4

Canon 430 II Flash

I am going to be researching this like crazy. Its not getting the shots that I am worried about, it is getting the composition for the shots right. I would really appreciate if you guys could point me towards some links that you think would be beneficial in this regard. Also, is there any other equipment that we MUST have to pull something like this off?

Edit: Please dont tell me to use google. I will obviously be doing that as well, but I would like to really focus on sources that you guys(the pros) find to be beneficial.

Thank you!