lenovo x200 thinkpad wireless external adapter

Hello everybody, I hope you all are fine.
First of all, I know this topic has been discussed on the forum sometimes, but as the topics are blocked (a thing that I don't understand very well...) I resolve to initiate a new one here. So, sorry and thanks in advance for you patience.
A couple of months ago I bought a lenovo thinkpad x200 to a friend. It was a good deal I think because I managed to pay only 200€ for it. I was excited and then I try to move from my old emachines e620 Gnu/Linux Trisquel laptop to that recent one, but I failed. And failed why? There was no wireless signal after the Trisquel installation on the Lenovo x200. I did some research of this incredible forum and came to know that wireless it was not possible in a x200 lenovo laptop. Somebody suggest to buy internal or external wi-fi card/adapter on thinkpenguin store, but super honestly the prices are too high in my opinion. So I heard that maybe an atheros wifi internal card would fit, and I bought this on ebay:
http://www.ebay.com/itm/Apple-Atheros-AR5BXB112-AR9380-450Mbps-Mini-PCI-E-Wifi-Card-for-Dell-Acer-Asus-/190722777110?hash=item2c67f6a016:g:rMUAAOSwk1JWfK~M
But guess what, no. This don't do the wireless thing on a lenovo x200!
I consider to forget Trisquel and move to Debian or Ubuntu, but as I am stubborn (And like freedom and free software!), I will try and external wifi adapter, and won't mind to carry it with me all the time.
My question is: I may buy an external adapter on ebay for cheep, but and then if I have the same problem? I would very much count with your experience on this, and ask for your help here, please. I would thank you a lot on this one.
My goal is simply continue to use Trisquel, but on a lenovo thinkpad x200.

Hugs to all and have a good week.
cheers