Well is gDial the official GV app for your platform or is it third party?
When using the GV app, you only need to run it from your phone once for the phone portion, after that any call to your GV number comes directly to your phone, theres an option in GV to make every outgoing call your GV number, ask everytime you dial or only for international calls, or never.
I have it setup so everytime i make it phone call it asks me what phone number I want to dial.
WHen sending texts as of right now I belive you have to use the GV app, when someone replies, Im not 100% sure if you reply usiong your messaging client weather or not it knows to use your GV number, although for me anyways using the GV app isnt much of an issue as its pretty fast almost like a native app. The only thing that annoys me is i get a GV notification and then a text notification that i got a SMS messaged and im not sure if you can turn that off as of right now