You can buy a tool from your local auto store, I think they are called brake spreaders. Will set you back about $15-$20. I wouldn't bother with it though, I had trouble finding a leverage point for it to push the pistons back in and ended up using my fingers (ouch).
The QFM hpx brake pads dont squeel. Dont know why you guys are getting squeeling from them, you've probably got track ones on