hi compass kath,
you'd probably be better entering this as a new thread, you'll get more replies that way. also there's been quite a few threads on the same topic as this. the general advice is - find out if there's a masters club near you and join them. if not - find a swimming teacher/coach who can help you. if not - read books (total immersion is a good book - you'll find alot of stuff on their website also). however, in my view (and i've been swimming for 20 years and teaching/coaching for 10) is that it's virtually impossible to train yourself at swimming because you can't look at your stroke and see where you're going wrong - you need someone else to do that.
however, saying that - by the sounds of it you're swimming with your legs dragging normally?? (hence why lifting your legs up helps?) so why not try pushing your upper body and head more into the water, there is a technical reason for this - but just try it and see if it works.