Easy.

1)
Run your wallet with your coins.
Go HELP/DEBUG WINDOW

click Console
type:
dumpprivkey
where is you wallet address.

Now you should get your prv key.

2)
Delete all Appdata to get clean wallet.

Run the wallet and Go HELP/DEBUG WINDOW

click Console
type: importprivkey
where is you prv key.

Start to sync.

That's all.