How much would it cost to soundproof my condo?

I just bought a condo and I can hear the person who lives above me walking around. It's not too bad, but I came from an apartment where I lived on the top floor so didn't have to deal with it. My condo is also above the garage, and when the garage door goes up and down, it rumbles throughout my living room. Only lasts about 10 seconds and isn't too frequent since this is only a 12 unit building, so again, not too bad, but would consider soundproofing the entire unit. It's a 2 bedroom, 1000 sq ft unit. Also, can it even be soundproofed?