Network set up with Time Capsule, AirPort Express and iPhone

Hello,
I'm trying to figure out how best to configure my network with a Time Capsule, Airport Express 802.11n, and iPhone 3GS. Currently I use my Time Capsule as the primary router. The radio is set to 802.11n (802.11 b/g compatible) and it is on Channel 1. The Airport Express is set up to extend my network. I have my stereo and Netflix devise attached to it. I'm running my Time Capsule in 802.11n/b/g because of my iPhone, but it just isn't all that fast. Is there a better set-up? For example, is there a way to run my Time Capsule in 802.11 n (5GHz), run my Airport Express in b/g/n, and connect my iPhone to my Airport Express? Is there a better setting for my Time Capsule radio?
Thanks

Are you saying that the 3GS runs slow on your G network? If that is the case there isn't much you can do.
Try this app
Speedtest – Xtreme Labs Inc.
When I use it I see a pretty standard bandwidth for my cable modem.

You could set the Time Capsule to transmit 5Ghz ssid. Airport -> Wireless -> Wireless Network Options -> Check the 5Ghz network name and change the name. Attach your Macbook Pro to the newly named network. IE mynetwork and mynetwork5ghz is how I usually have it setup. Note that it is faster to use 5Ghz if you have a fairly open house but any interference from walls, metal, etc drops signal and bandwidth much faster than the 2.4Ghz. I had this setup for a while but since the 5Ghz dropped off so much I stopped using the 2 network names. I tried putting my Airport Expresses on the 5Ghz network to see if it would help signal, it really didn't. The AEs tended to drop off the network too. Anyway I went back to the 1 name system. If I am in good enough signal the MBP will switch to the 5GHz automatically, but if I try to force it and I don't have good signal I lost bandwidth.