I forgot to add a transaction fee from a priv key I imported to my blockchain.info wallet.

Now it has 35 hours estimated but it has to be there within 24 hours or I lose the funds.

How can I get around this?

Why would you lose the funds?  You still have the private key, right?

It depends on the wallets that the sender and receiver are using.

With some wallets (such as blockchain.info) the wallet will stop broadcasting the transaction after a while and eventually the network will simply forget it existed.

With other wallets (such as Bitcoin-Qt) the wallet will continue to rebroadcast the transaction forever waiting for it to eventually be confirmed.

This seems to be happening a lot lately (or maybe I just noticed it because it happened to me yesterday).  Here are two other related threads:

https://bitcointalk.org/index.php?topic=327927.0
https://bitcointalk.org/index.php?topic=327818.0

The network will forget the transaction, not the BTC.

You're question can't be answered accurately until we know exactly what wallet the sender is using, and what wallet the receiver is using.

The most likely possibilities:

Both wallets stop transmitting the transaction.  The number of bitcoins that the sender's wallet calculates and displays increases by the sum of bitcoins sent in the transaction to addresses outside the wallet plus the transaction fees.

One of the wallets continues to re-transmit the transaction on a regular basis.  The transaction remains waiting to be confirmed at some time in the future.