thanks for the tip but i’ve been there and got nothing done...
my router don’t have the port forwarding option.
then again... i solved it myself!!! 
this is a step by step tips for everyone else that got the
same options like me.
1 - login to your router 192.168.1.1 (depends on your config IP)
2 - find the Advanced Setup tab... for me there’s 4 options in
the advanced setup. Firewall. Routing. NAT. ADSL.
Now... click the NAT tab
3 - There’s 2 more options here... DMZ and Virtual Server.
Now click the Virtual Server.
There you go ... in the application scroll choose PPTP and
add your start port number & your end port number...
enter your local IP then save... Reboot your router!!!
Done. 
