Did you manage to get the information you need? Based on what you said I would suggest buying a wired network card... I've run wires around my house and it is much better than any wireless... That said I don't hate any AC devices. If you are worried about cost I would suggest you consider of any of your services are actually AC. As an example this would upgrade done computers for less than a tenner
http://m.ebuyer.com/263123 (hope I'm allowed to post that... Sorry if not... I'm not getting anything out of posting that just an example of how cheap upgrading a wired network card is).
My comments are based on my experience and knowledge... Although in the spirit of this thread I do have a degree in computer science and do work as an IT manager so making stuff like this worth of generally my problem. Hope this is helpful.
P.s. Please don't buy any parts for a pic of you are not sure they are the right ones. If in doubt you can always use a USB device which doesn't require much knowledge... Technically USB 2 is too slow for gigabit networking but in practice it is fast enough if you only need to max your broadband connection. USB 3 is fast enough but only any good if your machine supports it.