Idle Temperatures for XFX HD Radeon 6770

So, my HD 6770 idles at 44-45c. It used to run idle at 39-41c. But last night, when I took out my GPU to see if there were any problems/dust because it has been making this weird continuous buzzing noise, I placed the gpu back into the slot and my idle temperatures started to remain at 44-45c.

The only changes I made when I took out the GPU were: (1) used a compressed air to blow out the dust around the fan, (2) attached that XFX sticker onto the center of the fan (at first, I had no idea what the sticker was for..), and (3) tried to unscrew the fan to see what the problem was.

My ambient temperatures are still the same as before.

Air flow in my case isn't that very good because it can't be modded. In other words, my case doesn't allow me to install another case fan. I could go buy one, but.. they're a bit expensive.

So does anyone know what the issue is? Did I not place the GPU fan correctly? Is 45c an okay idle temperature? Usually when I game or under load, the temperature stays around 57-60c. I haven't really seen it go above 60c though..