I'm using GUIMiner too. If you're mining off a pool then you'll have to check how they pay out and etc, block hashes found are your share of calculation that is completed, the number in the brackets are over the past 1 hour (1775 total since guiminer is fired up - 68 in the last hour) Stale means someone solved that hash and was accepted before you did and therefore that hash you were doing was not counted as a share.
If you're mining solo thru the Bitcoin Client server then I suggest you start by joining a pool and read more. Head over to my newbie guide and see if it helps. I'm still a newbie myself but I help whenever I can