the forwarding tab should allow you to put a port range that you want to forward, then enter the ip address of you computer in the port to forward it to. my experiences show that you need to start the torrent up after you make these changes or it doesnt show up as having your ports.
(also, with my dlink, this is done via a firewall tab, that has a similar allow interface, if yours is like this i can go into more detail on that)
as far as the manual announce, it basically sends the updated upload/download information to the tracker (thats my understanding of it anyway)
-Darth Simon