Thank you both for the responses!!! I did not follow either instructions yet, because I was not sure of some things which I will ask further below.
But before I ask those questions.... While I was waiting for a response here.... I decided to put my Wireless G Router BACK into the picture, and then I disconnected my ATA because I was so frustrated. So ATA was then out of the picture.
I decided to give X-Lite one more try (this was before I read your reply Red Leatherman), and for some miracle, this time X-Lite connected and showed my sip sorcery username. At the same time, I FINALLY had something show under SIP Bindings!!! There were 2 Bindings which read almost identical.
So I tried to call my sipgate number, and my X-Lite never rang. But when I placed a call using X-Lite, then my cell phone got an incoming GV call. I even tried calling my GV from another number, thinking that X-Lite would ring (instead of calling the sipgate number as I initially did), but X-Lite never rang either.
Anyway..... I wanted to post this first, just to say that I seemed to have gotten one step further (because X-lite could not connect at all, and because I had nothing in Bindings)
So I thought that X-Lite worked because I had disconnected the ATA. So I quit/closed X-Lite, and put the ATA back... but... as in Modem ---> Wireless G Router ---> ATA
My ATA still does work. Actually, in the ATA's Admin page, there's an Info Tab, and it shows "Not Registered" for Line 1. So I think my ATA is not connecting to sip sorcery at all.
@stuartofoz - 1- There is right now, a Binding, but I don't see it say "User Agent" anywhere on that line... So I guess that one was from the X-Lite. 2- Which one I prefer?? I don't care. Gizmo or Sipgate, as long as it works on my cordless home phone, and the call quality is good. 3- Yes, I have a Sipgate account and the free number they gave me is green/online. 4 - I did a test call, but nothing rang.. my ATA did not ring...
@Red Leatherman - Haven't tried your instructions yet, but already have a question: I did not quite understand how to add the Gizmo credentials to my ATA, because with Gizmo, all there is, is a phone number right? So do I leave all the other settings for the ATA the same, and just change to Gizmo phone number and password??
Anyway, thank you both for trying to help. Wish we could talk on the phone, as this would be much faster to figure out. I can add the GV Call Widget to my website if anyone wishes to call me... let me know and I'll add the URL here.