Lee
Not sure if this helps, but they said my PC has PCI e 16x expansion slot
Power Supply 300w
Earlier models of your PC had a 250w PSU. You must have the later model that come out with a 300w PSU.
Your PC is not designed for anything but very moderate gaming. If you want a gaming PC, it takes more that just fitting a serious video card. It needs a case designed for extra fans (3 to 6), a quality 3rd party power supply and a 3rd party CPU heatsink like so:
SDC10185_edited_2.jpg
That said, stay within the video card model guidelines in my last post, as you do not need heat issues which you will surely have otherwise.
If you wish to buy a GT 440, go for it. Just make sure is is a slim-line card.
Cheers,
Lee