I purchased a 2002 Mercury Cougar last year I.

Hi I purchased a 2002 mercury cougar last year I have about 130000 miles on it. The past couple months I've noticed a shaking of the break pedal when I push in and sometimes have to push harder for a complete stop. If I do a hard stop my breaks also sometimes squeal or squeak not always but sometimes. I also can feel the shaking in my steering wheel. I was wondering if you could tell me what this could be and how much it would cost to fix it.