How to open new wallet into Bitcoin Core and switch between?
the funds are linked to your "compromised" keys. They are not in your wallet. So you can generate a new set of keys (as you mentioned, by creating a new wallet), and then transfer from old address to new address. Before you start anything, think of backups! Procedure might be like this (attention: wallet dirs on Windows, Unix and OSX locations differ, depending on your OS, you may want to adopt): 

0.) stop bitcoind or UI
1.) backup of old (compromised) wallet to USB stick
2.) rename bitcoin wallet directory to s.th. like "OLD_bitcoin_dir"
3.) start bitcoin (it will create new wallet and keys, get one of the public keys via MENU-&gt;FILE-&gt;RECEIVE ADDRESSES, cut&amp;paste or write it down)
4.) stop bitcoind or UI
5.) rename wallet directory to s.th. like "NEW_bitcoin_dir"
6.) rename wallet directory "OLD_bitcoin_dir" to your original name
7.) start bitcoin
8.) transfer your funds to your new address from step 3
9.) wait until you "see" in a block explorer your funds on the new address
10.) stop bitcoin
11.) delete wallet dir
12.) rename wallet directory "NEW_bitcoin_dir" to your original name 
13.) check if funds are all there
14.) don't forget to backup again :-)


Hope this is the way to go, if there is an easier way within Bitcoin Core, I'd be happy to hear from the experts...