@buusil 

The only way I can see there being a way around this to continue using your tp link router as a router and not a AP is if your isp router allows it turn off all the isp router functions like dhcp ect. 

I'm not entirely sure you won't end up with a double nat. 

Not sure where your located but here in the UK i can only think of one main isp ( Virgin) that gives you a supplied all in one that will let you turn their unit into a modem only then you can use your own router as a main  ( how my friend has hes set up)either than that all it leaves you with is to the best of my knowledge  is the very limited option to turn off the isp options to somehow make it like a modem only (if options allow it. )  

Some isp you can do away with their units and use your own ( like me, I'm with BT FTTP)

I'm connected via pppoe and it was fairly easy to obtain details online to input on my router, 

Failing that you could speak to your isp depending if you can just use your own they may give you the details like username/password ect