RICE

Rest
Ice
Compress
Elevate

It's prolly too late for your injury, but it bears repeating. Rest the injured area or joint, put ice on it to reduce swelling, compress it (with an Ace bandage or brace) and try to Elevate it higher than your heart. That last one is a bit tricky, so do your best.

After an hour or so with the icing, I usually take a large dose of NSAIDs -- ibuprofen, Aleve, or one of the other over the counter ones. The analgesic effect reduces the discomfort, and the anti-inflammatory effect speeds healing. Keep on the NSAIDs unless they give you upset stomach. A little starch or tea helps with that.

You can really cut a lot off of both the healing time and the pain by following this advice for serious bruises.