I want to buy a repeater... But which one?

Not exactly. If the two back to back access points are on different no-overlapping channels (i.e, 1,6,11), they can transmit and receive simultaneously. Therefore, they are full-duplex and do NOT suffer from the 50% bandwidth reduction caused by simplex repeaters. This is the way I do all my repeaters. Well, all of 2 of them as I really don't like to use repeaters where a bigger, better, and usually uglier antenna will do as well or better.

Why does it only rain on weekends?

You have my condolences. Usually I'd say get a repeater that's from the same manufacturer as your AP, but I've had so much trouble with D-Link products that that's probably futile.

Repeaters are going to slow down your network, are going to cause you security nightmares, and are going to be difficult and expensive to deploy, configure, and operate.

I'd suggest changing the placement of your existing AP and/or antenna, shortening your antenna wire (as you suggested), or trying a different brand of AP before trying the repeater route.

Yes, but since each repeater will cut your usable bandwidth in half, you'll be down to 1/4 with two of them.

thanks mate, doesn't sound too good..

so if placing AP in another corner/room/ouside is not an option, which manufacturer do you recommend for AP and repeater(s)?

Why not investigate adding a high gain arial ?

Well, I've always liked the Linksys products, but haven't had time to mock up a multi-AP network and see how roaming works. I almost ordered a couple of Linksys APs last week, but I have to ensure I have the bandwidth to fiddle with them before I order them, or they'll end up in the "unused expensive bits" pile...

I just ran across

Check out the DWL 800AP+. Don't know if it works with the model you have, but it works superbly with my DI-624 Rev C wireless routers.

Dunno if the "+" is any better than the original DWL-800AP, but I've got three of the latter that I had to hardwire to each other instead of using in repeater mode due to all kinds of problems (lockups, one-way data transfer, etc). D-Link wasn't very helpful, and their policy of not accepting returns for products that don't work according to their spec had put me off them...

The + means that it uses the TI ACX100 chipset[1] which I consider to be excellent. All support PLCC (22mbits/sec) which should be disabled or it causes erratic traffic flow. I think (guess?) that the non-plus DWL-800AP uses Atmel chips. As far as I can tell, they are radically different products, with radically different hardware, different firmware, and different FCC ID numbers. However, minimize stocking and return issues as DLink switches vendors, the package and model numbers remain roughly the same.

I consider repeaters to be an abomination but will spare you the rant.