Weak Wifi Signal. Missing contact on motherboard?

Hi guys,

I recently got my hands on a iPhone 4 16gb, everything on it is working perfect except for the Wifi, which drops as soon as I move even a few inches from the router. I have some experience fixing iPhones so took it apart and noticed after making comparisons with another phone there's a circular copper point on the motherboard that the Wifi antenna makes contact with missing. Has anyone any suggestions on how to fix this?

Thank you

Tom