Tattoo74 - are you running it through an AEX and TC? As in extending your current wireless network from the Time Warner router to Airport/TC?
If so, my suggestion would be to ensure you disable the wireless channels on the time warner, and 'create' a new wireless network through the TC (on this, it will need to be 'Create a wireless network', and 'Off' (Bridge Mode)) - in essence, disabling the wireless mode on your DSL router and allowing the TC to control that side of it (your DSL will still act as the DHCP server - i.e. issuing ip addresses) - you then need to extend your network to the airport express from the TC..
Remember, the AEX acts as 'another' wireless client on your network if you extend it in this way, so will hog the limited/maximum 54 mbits of bandwidth available via wireless - result = lower download speeds...
Also, if you have any other macs/PCs drawing from that wireless network, they will suck-up the resources, and if they are not 'n' enabled, your wireless network will work at the lowest common denominator - i.e. b/g, and not 'n'...