Because I thought I could
Join Date: Dec 2004
Location: Wash DC Metro
Bikes: November, Trek OCLV, Bianchi Castro Valley commuter
The only piece I can imagine being bent is the slotted tab that holds the brake pad. To a limited extent, I think you could straighten it (or have a bike shop do it), first removing it from the bike, of course! It sounds like it bent in such a way that the brake is still functional and not dragging.
Or are you talking about the STI lever? Fixing that is going to be difficult-impossible as they aren't built to be rehabed. (I messed up the front (left) STI shifter on my road bike and ended up replacing the pair of STI levers/shifters). wpflem is right - a picture posted to the bike mechanics forum will be your best bet to get help here.
If the bike is rideable, take it over to your LBS of choice - worst comes to worst, they can replace it with a Shimano 105 or Tiagra component - same functionality, just won't look a pretty and weigh a little more. You can do the Ultegra part when someone has a sale (calipers are pretty inexpensive, it is the levers that cost $$ but Ultegra-9 is coming down as it gets replaced by U-10 components).