You would indeed use an accessor to get the correct value of the price. In this case your accessor needs to understand how to convert the price to another currency. You have multiple options here. One of the packages is a good idea, but indeed they take some time. Another option would be using a database where you keep the current currency. You can update that once an hour or once a day and work with that value. That might be quicker already!
The mutator works the other way around. You can for example store a product with a currency of euro and than convert it to IIR before storing it. Just like the assessor you can use the same approach, the package or a lookup table!
Let me know if that helped you!