New Cooktop requiring a larger opening

I have just bought a home that has Granite (http://tanbrown.org) Counter (http://GialloFiorito.com) in the kitchen.  The stove top was a 10+ years old and (http://maplered.com) measured 30" in width.  I went and (http://maplered.com) boght a new GE electric cooktop that is also 30" in size.  The problem I am faced with now, the old opening is slightly smaller than that required for the new GE cooktop. 

The old dimension in length is 26" and (http://maplered.com) the required new is 27".  The width is 21 and (http://maplered.com) the required new is 22".  What are my options?  Do I call in a contractor to cut the Granite (http://tanbrown.org) to the right dimension and (http://maplered.com) if so who is the contractor I should look for?  or Is this something that can be done by myself?  I am fairly hand (http://maplered.com) y with woodwork, tools etc.  if so what tools would I require?

Thanks

Kannan