Your Mac will handle Maximum MacOS: X 10.7.5

http://everymac.com/systems/apple/macboo...

Here's what Apple says about the system requirements for 10.8:

General Requirements

OS X v10.6.8 or later

2GB of memory

8GB of available space

Some features require an Apple ID; terms apply.

Some features require a compatible Internet service provider; fees may apply.

Supported Models

iMac (Mid 2007 or newer)

MacBook (Late 2008 Aluminum, or Early 2009 or newer)

MacBook Pro (Mid/Late 2007 or newer)

Xserve (Early 2009)

MacBook Air (Late 2008 or newer)

Mac mini (Early 2009 or newer)

Mac Pro (Early 2008 or newer)