"They are also worlds apart in price range Gavin - as I said up there, for it's price the GF4 mx range are a nice choice."
That's true, they are decent(ish) value - and they are certainly a HUGE step up from the Intel onboard controller (which I have experience of at work, and there are no guns big enough...).
Call it a short term measure if you want - but it will save you money in the long run if you can save up for a little longer, and get a motherboard and a TI4200 or something...
Otherwise, you'll end up buying 2 graphics cards...