OpenOffice unit conversion

So I need to do a lot of mathy stuff in OpenOffice with charts and tables and such, but my group recorded all of our data in feet-inches (like 9'4" for example), and OO.o recognizes that as text strings instead of as a number, and I can't for the life of me figure out a formula that can easily convert all of the feet-inches directly into decimals. Google has been of no help.

I did it by hand for one sheet, but there's a few others that have a lot lot more data. I figured something could be done with regular expressions but I'm really not sure how the logic of those would work out. Something like recognizing something followed by ', then multiplying the number by 12, then adding what it found to be followed by ". But my experience in spreadsheeting is limited as far as figuring how to actually do that with cell references (text cells, nonetheless).

Hep!

Hi, I informed him of the love that are comma separated values~