Most home GSM repeaters sell for $175 to $500... not cheap The Nokia has very good reception so I'm guessing the signal in your home is quite weak. The easier route would be to pick up a phone that supports UMA calling over WiFi (assuming you have WiFi at home)-- unfortunately the Nuron lacks that feature.
I've used Wilson brand repeaters in the past and they work well. You'll need a package that includes the repeater unit and an antenna that you'll mount on or near a window. Make sure to get one that's for GSM networks and that has the 1900MHz band for T-Mobile.