bolt issues

[i heart square bodys]

when I was removing the bolts to take out my bench seat i snapped 2 of the 4 of them off as well as one of the seatbelt bolts. I have tried a lot of WD 40 and easy outs and they wont budge. heating them up isn't an option because (with my luck) the bolts that broke off were on the same side as the 3/4 full gas tank. some have suggested to drill them out and just put nuts on the other side of the pre-existing nuts , but I don't want to do a hack job on this truck. I considered drilling all of the holes out 1 size bigger and re-tapping them but I have no idea what the bit size would be that id need for both the seat bolts and the seatbelt. also not sure if id need fine or coarse thread.from anyone that's had this problem and solved it, let me know some suggestions. i am 17 and trying to have my truck ready for spring so any help is good ! thanks !