wi-fi weak because the main board ground is broken off

I bought a used iphone 4 GSM that needed a new screen,I replaced the screen but noticed on reassembly that the tab where the top longest screw goes to hold the WI/FI antenna plate and where the little chrome clip goes on that screw hole to make contact from the antenna to the main board on the little gold dot on the main board is missing. The little gold dot that is. Someone has broken off the ear on the main board where contact is made by the little chrome clip. I am hoping someone can tell me how I can fix this without replacing the main board which is cost prohibitive for me. Please someone help me!