Re: how can i get a signal?
That was the first thing you should have determined before you chose your carrier - which one gives good coverage in the areas you need. If you chose a carrier that doesn't cover the places you need covered you can cancel the account if it's within the cancellation period or live with it. (A signal booster is a fixed device - it's located in the place you have bad signal.)
If you had a good signal with your last phone on the same carrier, the phone could be defective - bring it in and have it looked at and/or replaced.