The Ricoh Europe website has no listing for a "Ricoh 6513". They do have a "Aficio Color 6513" model listed under the "Multi-Functional Products" section. All available drivers are posted on the manufacturers website.
ATTENTION: If you're searching for drivers for your color machine please go to the 'controllers' section and select the 'controller' of your color machine! Note: I have no clue what controller your machine has...
Perhaps you can figure it out by reading the info presented on their website:
Support/Driver Download Page:
USA Support: (this site has several Aficio 6513's listed ie: E-710, E-810, E-820, but nothing for Windows 7)
Note: You should probably contact Ricoh directly to get help/answers.