Worn LAN socket

My wife's laptop is getting old and its LAN socket has worn to the extent that no matter what cable she uses the fit is poor and when she's online she has to hold the cable as a certain angle to keep the connection . . . which is frustrating. Wireless doesn't work either. Apart from the obvious solution to buy a new computer what other options does she have. Her USB is USB2 I think so would USB3 to LAN connects work? I can't imagine they would given the difference in USB speeds. There is a slot in the computer but it's not very wide (you can see how technical I am!!) so is probably not a PCMCIA slot. Can anyone help please?

Mixing broadband packages

Sorry, but my question requires a long-winded explanation. Because of where we live, my wife and I cannot get decent broadband except through a satellite package which recently went down for two days. It leaves us totally isolated since the phone is also satellite and we get no mobile reception here either. So calling any technical support or anyone is almost impossible!! So we will get a landline installed but the basic broadband costs only marginally more and would be useful as back up when the satellite package goes down, though it's only 1- 5 Mb/s instead of 45 Mb/s. Rather than use wireless both my wife and I connect to our computers through Home Plugs which work well for us. My question is this. If both the landline broadband and satellite broadband are connected to a homeplug, what will I get when I connect my computer to my homeplug . . . a scrabbled mess or two distinct LAN connections that I can choose at random?