Are both sites able to access the Internet and do you have someone at the other end who you can trust to do simple installs? If so install Teamviewer and sort your problem, get RDP working and then uninstall it.
Teamviewer is at
http://www.teamviewer.comIf you don't have anyone you can trust at the other end then use Dameware. This can be push installed then again deleted when the problem is solved.
Dameware is at
http://www.dameware.comSnibborg