You might try checking out again. Two weeks ago, in Preview Mode, I tried to "buy" 2 of an item I only had 1 of and it was going to let me. Today I tested it again, and it now stops you from being able to and states "There is only one item in stock." It seems there has been a recent update/improvement regarding this issue, thank goodness. I was very concerned this was going to cause havoc otherwise.
To the original poster, I have found no way to export to csv. I keep a spreadsheet that I TEDIOUSLY copy and paste from. It's a huge time eater and one I wish they'd address. As many of us are sole proprietors, we just can't absorb the time this sort of lack of functionality causes and will discourage others from using GoCentral.