OVMS: How do I find out what version OEM to use for a windows 7 desktop monitoring OpenVMS database

I know I should be able to glean this info from Oracle Support or all the product matrices you have listed here, but I'm confused with the terms.

Background: I have been limping along with OEM running on windows xp, talking to my databases on the OpenVMS itanium server (v8.3-1H1).  I hadn't been able to upgrade anything before (despite numerous tries from Oracle Support) because the db server was stuck at 8.3-1H1 and the agent for that version didn't work with any later versions of OEM.

Problem:  Recently the Powers That Be here decided to take away my windows xp machine (no warning) and replace it with windows 7. I am back to the stone age of database administration, doing everything from command line. I now have reason to force the painful issue of upgrading the OpenVMS operating system to 8.4, so I'll be able to get a new agent, but I don't know what version and I don't know what version of OEM that will be compatible on windows 7. I went to the' Schedule of Current Enterprise Manager Releases and Patch Sets (10g, 11g 12c)