Multi currency problem

Hello guys, I’m new to this forum community, and I would like to ask you for some help.
A few years ago I have made a website for the company I work for, but because the boss has specifically wanted all the payments to go through Klarna ( a payment system available mostly in the nordic part of the world ), the licence he paid for only allowed us to sell products in SWEDISH KROWNS ( SEK ), even though we offer all our services in SEK, NOK, EUR and DKK. Now that we have disabled klarna, I would like to add the missing currencies so customers from Denmark, Norway and Finland can pay in their native currency.
The problem is as follows… We have FIXED prices for every country, so a basic conversion plugin which will convert for example 540 SEK into DKK, will not be the right amount when converted. The price is based on the expenditure, taxes and other services we must use in the specific country in order for the customers from that country to have services.

Rough example.

3 months of our basic IPTV subscription for people who live in Sweden is 540 SEK, if we were to convert it to DKK for example, that would amount to 390 DKK, which would make the company go in minus for for 45 DKK, because the fixed price for our 3 months IPTV basic subscription for people from Denmark is 435 DKK ( formed by the expenditures and taxes we must pay for having servers and other technical essential stuff there )

So I need to know how can I make one article, have separate prices in separate currencies?

Thank you!
Lazar

The page I need help with: [log in to see the link]