You may want to contact an HP VAR to address your questions directly. Optionally, consider examining the printed system requirements for the version you are interested in.
It should be noted that both versions of LoadRunner which are are interested in are 32 bit applications. The server software which you note is a 64 bit operating system. There are no dependencies in Loadrunner which mandate the use of a 64 bit operating system or mandate the use of a server version of Windows. As a 32 bit application the addressable memory space will be limited to 4GB no matter how much RAM is installed in your server. If you are interested in a solutiuon which involves 64 bit Load Generation then consider the latest version of LoadRunner, version 11, which justy began shipping.