We use our mobile phone as our primary phone line. Since it's with us all the time, that's extremely convenient. However there were circumstances that when we were stuck with crappy reception.  

If you regularly deal with bad service like one bar or salvageable service in certain places in your house, there are a few things you can do. 

:) Find the areas in which you get service: If you're lucky, there may be a few spots (like by windows, doors, or away from big appliances like TVs and microwaves) where you get service.  

:) Use a Bluetooth headset: If there's an area of your house in which you get good reception, a quick and easy solution is to pick up a Bluetooth headset. Leave your phone in a good reception area, and just talk via Bluetooth.  

:) Upgrade your antenna: If your phone supports installing an external antenna (which many do, nowadays), you may be able to buy a inexpensive external antenna and an adapter for your particular phone. 

:) Try another phone: Again, it isn't ideal, but if you found that part of the problem is your phone, using a different one might help you out.  

:) Install a repeater: Sadly the most reliable option is also the most expensive, so better think and decide wisely if it is necessary.