The PCs are only usually usable by staff and students. We can sometimes get guest logins set up, but I can't promise that'd be allowed for external people. I'll look into it though. The policies are fairly restrictive, so while they do run AGS and AGS games (they're Windows 7, so do it by default), we wouldn't be able to install anything useful like Photoshop and such for game dev.
I'm looking into the 10:00 - 19:00 thing, and will investigate a more solid price.