Hi dwmosman,
You can install and run Toad 13 beta alongside Toad 12.12. You need the last GA version in order to run the beta.
To download the latest beta, visit our beta page here:
https://community.toadworld.com/products/toad-for-oracle/toad_for_oracle_beta_program/
Toad 13 should be released sometime around the May/June time period.
-John