I should also point out that wireless streaming, even using a state-of-the-art consumer router, will likely have buffering/performance issues with HD video. Practically speaking, your storage, media streamer, and TV should all be wired.
If you're looking for a more economical solution and have a limited video/music/image library, there are other manufacturers that offer media streamers with built-in 3.5 HDD support (e.g. Netgear). I would definitely look into upgrading your router, as FurryNutz suggests. The DIR-857 is a solid router with excellent performance.