This site is very strict about recommendations about products and services, so I will not come up with any links to banks or other institutions, but I am trying to provide some hints.
I assume that you currently have residence and an address in Austria and you have a current account in your name with a bank in Austria. So possibly, it will be the easiest to try and keep that account, IMHO. Opening a different (new) bank account under the assumption that you will be a non-EU national without a residency in Austria might become difficult to say the least.
So it would possibly a bit of: Let's assume they will not find out. You could arrange an address (I think just an address would do) to give you your bank simply as your "new address" so if they feel like sending anything to you it will not bounce back.
That might be the address of a friend or some kind of maildrop. The latter one would cost a mothly fee, but on the other hand, if you want to shop for tangible things in Europe you would need a delivery address anyway.
I have no idea how much money we are talking about, but you may also consider signing up for some kind of prepaid credit card. You will need to do this while you are in Austria. Then you can pay in the money into that credit card account and just spend it for online purchases. Just double-check the limits. Some of those prepaid credit cards have limits how much you can load onto them; sometimes it's in the lower 4-digit EUR range, sometimes in the lower 5-digits, but this is the maximum I know of. Note that the issuers of such prepaid credit cards need to make a living, too, so they will usually charge some percentage from you for loading it. Check the fine print!
Maybe you should to both unless you already have a credit card for your current account.