Well, shit, i didn't realise there was a duplicate thread. Here's what i posted in the other one:
Well, R.W. Burchfield has this to say about the use of "sat" as a present participle, as you're using it here:Now, the examples given here are all present tense, and yours is past tense, but the use of sat as a participle replacing sitting follows the same principle.
Personally, i think sitting would be more standard, and would be considered more grammatically correct. The thing is, though, sat is used by people from certain places, and in certain circumstances. What you have to look at is the context of your writing. If the character using the word in your example is a fictional character who would, in fact, talk like that, then there's nothing wrong with using it. If, on the other hand, you're writing a non-fiction piece and using the word as part of a merely descriptive sentence, i think sitting would be better.
Also, have you considered the possibility of using the participial adjective seated?
"We were seated at the bar...."