I think I see what you wanna do.
But I am still a bit confused about your connection. is it like a standard household connection?
Your "hotspot" is probably a PPPoE connection (The POE you mentioned has nothing to do with this - POE just means power-over-ethernet i.e. just another way to power your mikrotik)
The PPPoE connection from your ISP probably only offer one, max two IP's, so if you want to be able to connect more PC's I suggest to set up your Mikrotik with a permant PPPoE connection (connecting ether1 to your ISP port) and that you set up a NAT and a DHCP server to Distribute IP's to the PC's you connect to your LAN (wlan1, ether2, ether3).
Let me know if this makes sense, then we can probably help you with some tip how to set it up.
What IP does your PC have when you connect directly to the hotspot? Please also check what your public IP is (
http://www.whatsmyip.org).
Which Mikrotik router do you have?