The problem is that you use masquerade.
Which means that all IPs from 192.168.0.0/24 network will use Gateways IP address.
What you need to do is to configure src-nat and dst-nat.
Assume that youre PC address is 192.168.0.5/32 and you want to access it from internet.
Go to ip firewall nat and place following rule on top of masquerade
add chain=srcnat src-address=192.168.0.5/32 action=src-nat to-addresses=xxx.17.7.x/32 to-ports=0-65535
then do dst-nat
add chain=dstnat dst-address=xxx.17.7.x/32 action=dst-nat to-addresses=192.168.0.5/32 to-ports=0-65535
This should be done for each address (PC) that you want to access from internet where x will be one of the addresses asigned to you by ISP.
all other will go through masquerade!
I drink like a pirate and smoke like a hippie...