If you find those wheels constantly cracking (despite being a careful driver) I'd say just get a new set of wheels/tires. If the tires are still usable, take them off and sell the wheels (the ones that aren't broken) and maybe sell the tires as well.

I would suggest getting a set of 16's with 205/45/16. If you have a particular style of wheel, I could suggest a set, but I don't know what you like.