Did you mean like this /ip route add dst-address=10.111.111.1 gateway=10.10.10.161static route on mikrotik
But how about the web app, it cannot be ping to 10.111.111.1 from the PCyep so .161 doesnt know how to get back to you, which likely means you are presenting as your internal IP 192.168.88.x. Like a normal internet connection, you'll need to NAT your connection out of that interface.
/ip firewall nat add chain=srcnat action=masquerade out-interface=<whatever interface the leased line is in>
(or similar)
this should get you working.
Oke It's Work from My PCI've steered you to the likely answer - give it a go and tell me if it works. If you are not understanding what I am explaining then perhaps this task is beyond your capabilities and you should hire someone to help you. My explanation explains why you would not be able to ping the web server from your PC (until you add the NAT rule).