Port forwarding question

I have a draytek 2920n which has 20 port forwarding slots, I now have used all and I need to add another

Can anybody help, what are my options, if any, not a network guy, so only basic knowledge

Is there any similar kit with more than 20 ?
phil

Update
Wrong model, its Draytek Vigor 2920 Dual-WAN High-Speed Ethernet Router
Corrected above

are you referring to a router here?

yeppers I believe he is.
http://www.draytek.co.uk/products/legacy/vigor-2930

Mark

Sorry, got the wrong model in first post as well. (corrected)

its Draytek Vigor 2920n Dual-WAN High-Speed Ethernet Router

I think you’re gonna need a more capable router…