If I understand correctly, you are looking for a way to let your device work as a switch with accesspoint functionallity.
This can be easaly done by resetting the device with no default configuration:
http://forum.mikrotik.com/t/solved-recover-from-no-default-configuration-system-reset/65161/1
Then create a bridge and attach all the interfaces.
Configure DHCP client and WiFi and you’re done.