Network Decisions can remotely administer a network or server to fix configuration issues, install updates, or maintain services. All that is required on your end is the installation of WINVNC, a password protected remote administration program which you can uninstall at any time, or the use of Windows Remote Desktop/Assistance services pre-installed in Windows Server 2003 and Windows XP. 

Remote administration using VNC or Remote Desktop/Assistance is 85$ per hour with a one hour minimum. VNC is available from the free tools area on this site. 

Long term remote support contacts can vary in price.  The standard contract is $500 per network per month and $150 per server per month.  Long term network support can include patching, monitoring, backups, basic troubleshooting, or other specific predefined needs.