tire going bad

i need some help. i bought some used gsr rims and tires a year ago for my 95hatch. the car is lowered with some coil overs, the question i wanted to ask is my tires in the back has big cracks along the inner part of the tire and the front tires are in good condition. i will buy a new set of tires soon but before i buy them what can i do to correct the camber adjustments in the back....will bolt and washer help and if so what size should i get and any pictures on how to do it..