How much for new mid 2010 logic board?

So I had my hard drive replaced and ever since then when I am using my computer if it gets knocked at all the screen will either go solid black, blue or orange. Why? I brought my computer into mac life and they said that it was most likely a bad logic board and to take it into apple and they could tell me right then and there what it was. How much do you think that a new logic board will cost? Also, how long do you think it will take to be repaired from the time I take it to the apple store? Oh! and also whenever I close the lid to my computer it doesn't go to sleep. I have a mid 2010 13'' mbp. HELP