I would recommend using a well endowed spotter in a loin cloth, you can also work your iron sphincter technique.

Seriously what Frost and Scott suggest are pretty sound, I'd even work one heavy, one light high rep day each week. I highly recommend doing deep knee lunges in addition to your squats...about 3 sets 8-12 reps each leg to start. Builds all the supporting muscles for squats and will help with that dreaded Asian disease noassatall.

Lastly I'd ask someone to check your technique...lots a simple little corrections you can make to improve your lift.