Complex Network Adapter Problems

Please bear with me.
Our house has an old Linksys Wireless-G Router that came with external USB Network cards.

I found that using one of those, my desktop can connect to the router, but gets about two bars of signal strength and provides a sluggish at best netowrk connection.

Eventually I got tired of it and bought a TP-Link WN951-N internal N Wireless card, thinking it would improve things.

However, when I would connect using only that, my signal strength averaged four bars, but I would be constantly disconnected from the router, making playing online games or chatting virtually impossible (even if for downloading or even streaming it was light years faster). Worse, after a certain duration - 8 or so hours, sometimes less, the card would lose it's connection to the modem, and would not even come up as an option in the Currently Connected To icon in my taskbar.

Resetting the Network Adapter (or disabling and re-enabling it, or choosing Diagnose as I don't know how to manually tell it to Reset unless the Diagnose button presents that as an option) does nothing, and it not only can't detect our router, but any of the other routers on our block. It just goes dead. The only way to resolve this is to restart the entire computer.

I found a compromise: by running both, I get the stability of the external card with the speed of the internal, and the bursts of lag from the internal 'clicking out' are negligible, but I still have the problem of the internal 'going blind' and being unable to connect to anything untill I restart the tower.

I've tried all kinds of driver solutions, and the only thing I can think of is that when I was installing the card, I broke the little plastic tab that holds cards installed in the back of the tower in place, and so maybe it isn't sitting fully flush, but every time I open the case and check it, it seems to be in place securely, though should I (ground myself and) touch it, it bumps loose fairly easily. However, nothing bumps against my tower.

Anyway, I'm sorry for my problem being long and confusing, and I know that purchasing a new router (we tried that actually, but we can't get our brand new router to install properly) or taking my computer into a shop and having professionals look at it (though money is a serious issue right now) might fix it, but I'm kind of hoping it might be something simple and easily fixed.

Attached is my Dxdiag, any help or assistance would be appreciated. :)

when the card goes dead if you open network and connection sharing and go to change adapter settings, choose disable then wait then enable do you get the connection back? are you taking a usb stick in / out while your online? is there anything on the USB that might be set to auto power on / off?

No, disabling then enabling after a time does nothing.

When things are operating normally, if I click the Connection icon in the taskbar, it shows me USB Connection (the external) with a long list of routers each with 1-2 bars of signal strength, and Wireless Connection (the internal) with only 4 of those options each with 3-4 bars of strength.

When the internal 'craps out', Wireless Connection isn't even an option on the list. I can then go into Connection Sharing and disable/enable or Troubleshoot, the former doing nothing, the latter saying Troubleshooter Could Not Find a Solution.

Resetting the tower itself however will restart it just like Resetting the Network Adapter should