There are two types of brake bridges.
1. Cheap piece of tubing with a hole in it.
This is why they call me the Bike Butcher of Portland. In this case I'm hacking the bridge out prior to removing the seat stays for a repair.
Then there's the nice ones that are cast with flats on each side.
Recessed bolt version from framebuildersupply.com - just one of many examples
The first kind typically has some slop in it, you can rotate the brakes a bit due to the hole being oversized. They use conical washers on each side for the bolt and nut to have flat purchase on . The second type has a flat that the brake bolts up against, no slop.
Lynn, yours appears to be the first type. You might try loosening the nut, swivelling the brake and tightening it down. Braking forces will make the brake want to rotate back in the direction you want. Indeed, most centerpull brakes tend to touch the seat stays for this very reason.
If the hole isn't tangential to the rim, and the brake bolt limits how far you can rotate it, I wouldn't worry about it. Looks to me that it's an aesthetic issue. If it really bugs you, take a rat tail file and carefully remove some material so that the entire brake is perpendicular to the rim.