To Update your Wallet,

Close your current wallet,

Download the new ULI version

Website Zeit-coin.net has the No-IRC version if you are using one of the antivirus that are reporting the wallet as a false positive : https://bitcointalk.org/index.php?topic=487814.msg20412243#msg20412243

If you are not using one of the false reporting antivirus,
or you don't mind excluding zeitcoin-qt.exe from your Scanning until we get that false positives issues sorted.
Then Download the wallet with the IRC code from here:
Windows 2.0.2.1 Alternate Download

Then just start the wallet like normal. But do so before August 11th.