If I lived closer to you I would do it for you. But seeing as I dont, any computer shop would do this but your better of going to one of the small town shops instead of a big name brand computer store.The small town computer store will have better service because they need your business the big corporations, all they want is your money.
It really doesnt take much to do. Make sure you have completely drained all power out of the system. By this I mean turn it off,switch your power supply off and hit your on button on the computer. Doing this ensures that all the power on the board and in the components is completely drained. Make sure to wear a static wrist protector to when opening up your case and fooling around inside, one jolt of static electricity and the component your touching is fried.
Next unplug and carefully remove the heatsink from the top of the processor. Most heat sinks are on with a little metal strap that is clipped to the side of the processor seat. Push down on it and in toward the processor. Be careful not to slide the metal bracket across any part of the board, this could ruin it. The heat sink should be off at this point.
Next is the processor, on the side of the processor seat there should be a little metal arm that if pushed down and out should release from the side of the seat. Pull this arm up (dont force it, if it doesnt come up then you have not unlocked it ) and lift the processor out.
Now replace it with the new one, drop the heat sink on and plug it in (All the time your doing this you have your static wrist protection on) Close the side of your case and now you should be able to turn on your computer with the new upgraded chip in it. Turn it on and see if it runs if you need your bios flashed make sure to follow all the instructions on the manufacturers website as to how to go about this.
These instructions may vary from computer to computer, they are just a general set of guildlines. PLEASE IF YOUR NOT SURE THEN DON`T in this case it would be better to get someone else to do it.