What can I do about a cracked frame?
It's hard to tell from the photo ( is that large vertical streak said crack? ), but if your frame is cracked, don't use it. Riding on a cracked frame is risky as it could result in a catastrophic failure / injury / death.

It looks like that's probably a steel frame, so find a local frame builder ( not your buddy who's handy with a welder ), and depending on the damage they may be able to repair it for you.