I shot a wedding with a 40D, 17-50, and 85. I was second shooter but outside of my lack of posing skills felt like I could have done it myself and had very good results.
The church was well lit, and the wedding was in the early afternoon, and with the faster lenses I was able to get away with no flash. We were allowed to use flash during the ceremony but opted not to. The posed formals were done with a pair of studio strobes thru umbrellas, which could be rented.
The primary shooter had a Nikon 18-135, which is a slower lens. She still got some great stuff during the ceremony, but she had a harder time getting stuff going on at the reception, where I had a flash.
I'd sell the kit lens and find a way to land those two lenses.