OAA is expensive but the APP course is very good.
So is their Modular Waypoint course.
Your Exam results are more than sufficient for self sponsorship, but you need a degree in any subject to stand a real chance for initial selection onto an Airline scheme.
I have commented on Pprune many times on the training Integrated/Modular argument, but in the current climate I might suggest the Waypoint scheme if money is tight, otherwise the APP course is the way to go. You should aim to finish either late 2011 or early 2012, when there should be signs of a positive upturn in the recruitment.
Just checked your age Get the "A" levels sorted then apply for selection, its valid for one year once you have passed.