iphone 3gs help needed

i have a iphone 3gs on orange and ther signal is fine in my house 1-3 bars , i bought a 3gs for my partner for xmas and got it unlocked coz it was on o2 and she is on orange but she cant get signal in my house why is this?

I had a 3gs on O2 and had excellent reception. Now I've a 4s and that's fine too on O2. About the only place I couldn't send from was inside the CCS.

StT.

Has her number/phone been signed up to the orange/Tmobile joint reception ? If not you can do this on the orange website....