Hello, I'm a VoIP specialist with 10+ years of experience working on the TS department of a US VoIP company; I can install, troubleshoot and customize many VoIP devices including: softphones, ATA's, IP-phones and PBX systems like Asterisk/FreePBX. I read your project description, and I can setup your Google talk integration with your Asterisk server. You may contact me through chat to discuss your project further and get started.
Thank you.