Computer newbies forum: Wireless dfficulties caused by i-pad and me

I should never have believed the guy in the shop who said it was easy to set up TP-LINK 150mbps Wireless N Nano router Model No. TL-WR702N (to give it its full name) as a repeater so that I could access the web with my I-pad from the West wing of my mansion through 20 m and three walls to my computer.

It comes with some short and to me ambiguous instructions in a bad translation from some oriental language. (BTW being in Italy I already have to contend with four languages, English, Italian, English computerese and Italian computerese and believe me fluency in the first two does not guarantee ease of translation between the second two.) Also a formidable nearly 200 pages of elaboration on a disk. So after some time-consuming misunderstandings I have changed my IP somewhere. They tell you to. But nothing I did changed the reach to the i-pad, it still only networked near the computer.

Computer was working normally yesterday when I did that. But switching on today the computer could not contact internet. The computer however can communicate wirelessly with my printers. Strangely, not initially, but afterwards for a bit the I-pad was definitely able to contact the web - e.g. I downloaded today's newspapers and posted on a forum using it. But after a bit that no longer worked either and I get signals like 'no network coverage'.

Now if I go into I-pad Setting , Wi-fi , Chose a Network, shows name of my domestic network, and TP-Link -number. Going to mine it shows an IP address and Subnet mask, all else blank. TP-link showed no info before, now what it does is ask me for a password. If I go the computer Network Connections one of the three icons that used to be there is now missing and the wireless connection Netgear WG111T icon Properties shows an IP and subnet mask different from the above two and also a 'Predefined Gateway' (it's called something else in English) number.

Is all I have to do is make the numbers in the two devices the same? which way roynd then? Or what? I am frightened of making it worse and losing the limited functionality like printing from the computer I need in the rest of this week before I have to leave for ten days. The wireless system was installed by a technician, I have no hope of understanding it (I do have a Wireless Networks for Dummies book but it is above my head).

One of the bugbears I've found is passwords. Instructions talk of passwords and they are sometimes asked. To me that could mean any of five - the password of the computer which maybe I remember, not sure, I wish it didn't have one, for all I know it is deactivated, the password of the wireless network, the pw that came with the TP-link device, the pw of i-tunes to which the i-pad is mystically joined, or a password I am supposed to invent myself. Anyway none of these ever work.

Is a quick way out of this in a short time obvious to anyone? I have got Windows XP to the best of my knowledge. I am writing and sending this from a netbook, I could not send it from the main computer for the reasons explained.