Airport Express - Problems with Airtunes and Network (static ip possibly)

Let me start by saying that I am a relative novice to network configurations when it comes to anything past very basic setup. I've set up a few wireless routers using automatic DHCP...but I am clueless to anything past that.

So here's my situation:

I am helping my parents with their network. It all started because their wireless coverage was poor in certain areas of the house. They have ATT U-Verse with a 2Wire HGV3800 router and it's at one end of the house and can't be moved. I tried a repeater, which did not work well. So I installed a Dlink DIR-655 802.11N router in AP mode and disabled DCHP - not sure exactly how I got it to work. The signal is now great throughout the house...but I am having problems with two things:

I have no idea how to set up:
- An Airport Express that is only used for Airtunes and nothing else
- an Epson wireless printer

Ideas on how to get Airtunes to work? Let me know what settings I can provide to further diagnose the problem.

You can put he Airport Express in client mode - then it is just another device on the wireless network. Once you have this setup - you can stream music using Airtunes.

Most wireless printers come with a disk that help you set it up on the network. I have not used Epson but I needed a disk for both the HP and the Canon network printers.

I have tried client mode (sorry, should have mentioned that) and I wasn't able to get it to work. My guess is because it's because I'm not assigning the IP addresses correctly...and I'm not sure how to do that. Does anyone have advice on how to do this? For beginners, mind you

Thanks

Well - can you go through what you did? Usually you just use the wizard that is in the Airport Utility to connect to a network. You shouldn't have to assign an IP address if you are using DHCP. The only thing that may be a hiccup is if you are attaching to a WEP network - there have been some issues with Apple products connecting to certain WEP networks. If you are using WPA/WPA2 then it should just be a password. Also if you have MAC filtering on you have to remember to add the MAC address of the wireless of the Airport Extreme (there are 2 MAC addresses printed - one for wireless one for wired)