Android :: Samsung Galaxy S Reception Problems

It seem that other people are having Samsung Galaxy S Reception problems. I unfortunately am one of them. In my bed room I used to get full 3g signal on my old phone, I am lucky if I get 3 bars now. At my dad's house he had 5 bars signal, and he usually is worse signal than me. I at that point had 0 bars, and my phone reported no service. Is this a hardware problem or a software one. I am not sure whether to return the phone or keep it, I really like everything about it, and some lag has been sorted in the custom rom at modaco, however I am not sure whether to try it, cause If I need to return it, I'll have voided my warranty.