OK, so to break it down, you need a wireless router with a built in switch (WRT54G would be my recommendation, although there's about 40000 different versions of it). You need something to translate from wireless to wired? Am I getting that right? I'm sure such a beastie exists, but I'm not sure where one would find one or if they actually work. I know you can do it with a second wireless router, but it takes some clever set up.
Although as I think about it, all you need are single 802.11e->ethernet converters, which there are plenty of.
The WRT54G is identical to your current router, as far as I remember, other than having the two antennae. You can get larger antennae for it, depending on which model you have.
