how can i fix my 3410? i cannot get signal?

recently i got my phone wet in the rain and on the same night fell over and my phone hit the floor, when i got home i could not turn my phone on, so that night i took the sim card out, both covers off, and took the buttons out and left it to dry out.
In the morning i could turn the phone on but cannot get signal. its been like this for about 3 weeks now and ocasionaly i get signal for about 2 minutes and then it goes again.
please could you help
(the phone is a 3410 and an O2 simcard)
thankyou