OS X :: Trying To Get Owner Permissions On Used Mac

I just bought my first Mac a month ago, and have since completely ignored my girlfriend for this new lover. I bought a MBA Rev A, used with a ton of software still loaded on it. The problem is, the guy I bought it from was a Korean exchange student, and set the comp with Korean as the native language. I did a password reset to get the language change, then set myself up as an Admin account. The problem I have here is that the software loaded on this laptop is awesome, but I can't update any of it because I don't have owner permissions.

I understand the only way to get owner permissions is to do an Erase and Install of Leopard, but if I do that, then I lose all the software. This laptop came loaded with Adobe CS3, Parallels, Office for Mac, Toast 9 Titanium, and I think there might be another program. My question here is, is there any way to gain access to these programs, by using a copying software to make disk images of them, or by simplifying copying down all of the Product Keys, and reinstalling the programs from a hard disk.