Where to buy GP tickets for Mugello race?

Posted awhile back about where to go see a race in Europe and we've now got the flights booked and going to see the Mugello race in July. I've looked around at many different websites and they have discounts running through 1/10/11 on tickets but my question is has anyone here used any of these places and were they good? Tyring to make it easy on myself. And if you've been there any suggestions on grandstand vs general admission.

Thanks!