Finally, I figured it out. All it need was a NAT rule which i was missing.
/ip firewall nat
add action=masquerade chain=srcnat out-interface-list=wlan1
For webfig:
Go to IP > Firewall > NAT
Set Chain to srcnat
Set Out. Interface to wlan1
Set Action to masquerade.
Apply the setting & save it and check if the rule is enabled. If everything fine you will get internet on bridged interfaces.
Courtesy of @sob
http://forum.mikrotik.com/t/no-internet-connection-on-vlan-virtual-wan/155859/1
Thank you everyone for guiding noobs like me 