EDIT: Oh wait, I think I've read that wrong. Don't believe you can make it bridge to the other WiFi, but it can act as a separate AP if you can run some ethernet cable? Not sure if that's any use.
Yep.
I think I've done EXACTLY that with a Sky Sagem router. There's no specific access point mode but it can be used as one.
Change the IP to something other than the 192.168.1.1 (as long as it's different to your main router IP - I just used x.x.x.2 - and change the DHCP range of your main router to exclude that. I just use 192.168.1.100-254 so I have some space below to set some statics). Turn off DHCP on the Sagem router. If you want to use it as an extra AP you can hop between use the same SSID, same WPA settings and key.
If you want a totally separate AP use a different SSID.
EDITED: 18 Jul 2014 13:36 by ANT_THOMAS