Can't set up wireless access point with Macbook Air

First, I'll say I'm one of the least technical savvy people ever. I like to plug things in and have them magically work. Anyway, I have just moved into a new flat. The property management company supplies the wireless router for folk to set up their own secure wireless access point. Trouble is the router has an installation disc for windows but no mac support what so ever. I have been on-line for a week researching and found nothing that has helped. I'm looking for step by step detailed instructions of how to set this thing up. Also to note, there are about 30 flats in the building all on this network with wireless access points.

The equipment: I have a mac book air (just over 1 yr old) and a trendnet tes638pap wireless router. I also have the thunderbolt adapter as I found the computer needs to be attached to the router via the lan port.

I can log into the router. I can name the SSID. I have found where to set up security WPA2 but it asks for IP addresses MAC addresses, etc. and I have no idea or where to get that information. I can set up a WEP with a password but research has stated the WPA2 is better. Once I do all of that, I can see the access point I created on my drop down box for networks to join. I can join the network and enter in my password. Then one of two things happens. It will assign its own IP address of 169.xxx.x.x.and I have no access what so ever or it tells me that the router is out of range (and funnily enough, it's right next to the laptop).

I don't know what to do here and would really appreciate any assistance. Thanks....