TheHorse is right. I had the same exact problem. I configured QoS on my home router (a Cisco 831) and I also configured QoS on my Linksys Wrt54g using the sveasoft firmware. (I have both wired and wireless clients on different subnets.)

The sveasoft firmware is necessary as it adds quite a few features that are not available in the normal firmware. You can find the firmware @ http://wrt54g.thermoman.de/ Get the latest version 1.04 right now. Make sure you get the appropriate firmware because you can't load the g firmware on a gs and vice versa.

I'd advise against the D-Link. I've had horrible horrible experience with them. You can see my opinion on those routers all over this site. Many others have had the same problems as me...

Going the "cheap" route... I'd do the linksys wrt54g... If you want to spend quite a bit more... the cisco is VERY nice. I love them and will always own them. They are so very flexible if you want to get down and dirty. If you just want to set it and forget it... then linksys is good.

They are not that expensive... around $50-60... well worth is if you ask me.
http://froogle.google.com/froogle?q=wrt54g