You can import your private key into a wallet that you can create. Keep in mind that you create a wallet....you are not looking for a file in that window that looks as if you have to locate a file.....so you just select where you want the file to be created and type in a name such as 'NEOwallet' for example in the desktop. You should then see a file that has been created called NEOwallet.db3 on the desktop. With that file you can import your private key to that new wallet address, but you should write down the private key of your wallet first and it is best to make backup copies of the .db3 file before importing the private key to the wallet. You also need to synchronize the wallet (there are ways to speed up the synchronization process and you should read up on it at the NEO Reddit unless you do not mind waiting for a day). The last thing you likely will need to do is to select the 'Rebuild index' option as otherwise your NEO might not show up in your wallet, even when they are actually there. You can also check your holdings via the neotogas website via your public address (even before your own wallet is synchronized).