I shot weddings in very dim lit situations with a 7D and had great results. For the ceremony, you should be able to use your flash before and after. I used flash for the walk up and walk out and it worked pretty well. Those times I used the Tamron 17-50 f/2.8 (non VC) and the Canon 24-70mm f/2.8L v1. During the ceremony, I used the 70-200 f/4L IS and it worked great. You can use lower ISO and a slower shutter speed with the f/4 due to the IS and the lack of movement during the wedding itself. There were times I switched to the 85mm f/1.8 when I was allowed to get close to the alter for the lower DOF shots. I used the zooms mostly during the ceremony because it is hard to zoom with your feet when restricted and you don't want to detract from the wedding for the couple or the spectators. During the reception and the dance, I used a 50mm f/1.4 and the 35mm f/2 (old one) with flashes. I had two cameras the whole time. Most of the reception and dance I shot with the 35mm since it was wider.

You can make your current lens lineup work if you don't want to buy anything new. Just make sure you have a backup camera in case something should happen even it is an SL1 or a T something. At the same time, don't forget, you can rent pretty cheaply from Lens Rentals if you are interested in the 2.8 versions of the zooms or a 5D mark 3. Just rent them for a whole week so you can get use to them.

My opinion has always been the 50mm f/1.4 is a good buy. It is not very expensive and f/1.4 is sharp enough. At f1.8 and above it is very sharp. Don't forget about the new sigma 50mm f/1.4 if you don't want to spend the extra bucks on the Canon f/1.2. Looks to be a stunner.