Hi,
Take a look at this site:
http://www.didww.com/coverage.php
Here you can register for a DID pointing to a sip-uri.
The setup is US$30, the monthly fee is US$70.
You can also try
http://www.sipbroker.com/
A free service, and register a number here at voxalot.
Register that number in your ATA, dial the sipbroker number +7-3452-591002, and dial *010xxxxxx#, where xxxxxx is your voxalot accountnumber.
Theoretically this should work, but I haven't tried it lately.
Yves