Connection problems with D-link equipment in repeater mode

Hi,

I recently set up the following equipment with the aim of extending my wireless range (across three floors):

Router: D-Link DSL - 2741B
Wireless set to b+g+n
Channel 1
On second floor

Access point: DWL - G700AP
Wireless set to b+g
Channel 6
Repeater mode
On ground floor

As far as I know neither the router nor the AP support WDS. I just set up the AP as a repeater and added the same SSID details as for the router (just a different channel)

The problem:
The network sometimes works fine but then seems to regularly kick wireless clients off the network and the only way to resolve the issue is to unplug and restart the AP.

Can anyone identify the issue? Does anyone have a solution? Thanks for any answers!