Internet access

Hi to everyone.
Sorry for my poor English.
I have a RB433AH with 3 wirelles interfaces.
The first one (wlan1) with another RB433 with ip 10.xx.xx.230/30
The second (wlan2) with routerOS pc with ip 10.xx.xx.140/29.
The third (wlan3) is my problem because i used it as client to AP for internet gateway.
I set it up to connect with the AP (it takes ips 192.168.xx.xx) but when i try
to connect my pc (ip 10.xx.xx.12) to internet nothing…
My eth1 has ip 10.xx.xx.1
I don’t know if the problem is the routing in RB or the PC settings.
Can someone help me?
Thanks in advance.

Set gateway of Wlan 3 as default gateway.