brakes

I just changed my front brakes and had a tough time with the passenger side. Everything came off easy but when I tried to install the new pads my caliper wouldn't fit right. When I got it on, the caliper bracket the opposite side of the rotor went crooked and had about half an inch that needed to be pushed back (only on one side). I put the tyre on anyway and doing so pushed the rotor to where it's supposed to be but now it takes a lot of effort to drive and without using the brakes it stops very quickly. What do I need to do to fix the problem?

There is a squeaking noise every time I apply the brakes. The pads don't need to be replaced; what could be causing this noise?