My old worship leaders (a husband and wife team) always tried to get me to stretch myself as a guitar player, and while it was a bit uncomfortable at times, it was the best thing for me and for our overall sound and worship experience.
Unfortunately, they had to leave the church a few years ago (because of a job transfer), and our current guy who does most of the worship leading is a fantastic blues player. The problem is, although he is a dear friend, he wants to play lead almost exclusively, and he wants me to just play chords. Makes me miss the days of being stretched.
So my point is, look at this request to stretch yourself as a fantastic opportunity to grow as a guitar player and a member of the worship band!
It always helps to have good resources, so here are a couple that have really helped me:
guitarpraise a fantastic website with videos for playing electric guitar in worship bands
A DVD called Electric Guitar with Paul Baloche and Ben Gowell(again, for the purpose of supporting worship)