Would you like to bring the offline wallet to online?
If so, just enter the private key of your wallet in
https://www.myetherwallet.com/#send-transaction and send the eth to another offline wallet.
If not, you don't want to expose your keys, then follow the procedure
1. Go to this page
https://www.myetherwallet.com/#offline-transaction2. Fill in the address from where you should send the eth (i.e the address which you hold your keys now) and press Generate transaction
3. Fill in the TO address info (to which address you should send your eth) and nounce.
4. Enter your private key and generate transaction in offline mode. You will receive a signed and raw transaction message
5. Paste them in Step 3 and click Send Transaction
Since you don't have access to the offline computer, I think entering your private key is well and good in mew website. But double check the url before doing any transaction or posting your keys.