You won't lose that stuff. You're just updating the software, not replacing any other data.
The blockchain is located in \bitmonero\
elsewhere and the wallets (with 3 separate files each, data/.address/.keys, the keys being most important) are located in the same folder as your wallet client by default. Replacing monerod, monero-wallet-cli, etc won't affect them.
You should always have a backup of your wallet anyways ;)