Remote Wireless repeater throughput problem

Hi,

I constructed a remote base station to extend my base station range.
It has worked quite well for using the internet form the main station (adsl2+),

I have recently built a Video On Demand server and attached it to my main router. when i try to upload movies form the remote location the speed starts off fast 2.9mbps and suddenly pauses after about 3 seconds it resumes and suddenly slows to 30kbps and seems to stay below 400kbps pausing and resuming contunuiously, i have setup queues but seem to have the same problem, I have lowed the MTU but it has made little difference.

I have attached a diagram. Is their a way to fix this of perhaps a better way of doing it all together?

I would appreciate any help

Kind Regards

Paul
Problem.jpg