Break discs causing squeaking noise

[we78]

Hi
Ever since I bought my bike (it's 2nd hand). The rear disc, which is slightly bent was causing an annoying noise each time it would spin since it would touch the pads.
I tried strengthening it myself and also had someone at the shop try to do it, but after about 10 minutes it only got worse.
I really hate this sound and I wish I wouldn't hear the squeak. The guy at the shop told me that the rear disc is very thick and thats why its hard to strengthen it. Is that true?
Is it worth buying a brand new disk which is less thick or will it get bent as equally fast?
Another issue is that, unfortunately, each time I go riding I have to disassemble the wheels off my bike to put it in the car and then re-assemble it when I get to the trails. So each time its re-adjusting the breaks, pretty annoying.
My disk breaks are 2nd generation hydraulic Hayes. I was wondering if upgrading to some 2012 breaks will solve this problem since some say "auto adjusting".

[Bill]

If the guy at the shop has the right tool and experience he should be able to straighten it rather easy. Straitening is also called find the truing. If it is a annoying thing to you I guess getting a new brake would be better. Yes newer brakes bend just as easy as your current one. You could go with a different type of brake called a v-brake if you have the mounts for them on the back of the frame. Picture of your brake would be a little more help if it is possible please.

[we78]

Hi
You can see the picture here
This is a pretty rough all mountain bike, V-breaks is no go

[GeorgeET]

With disc brakes if you cannot cut them on a lathe than you need to replace it. Straightening it with a press may weaken it and cause it to crack at a really bad time. You tried once now its weakened. Looks like a nice bike do it right......Get a new disc.