Use
hg diff >changes.patch
To create a patch of your changes. Then, go in the other repo, update where you need your changes to be, and issue
hg import --no-commit changes.patch
With the proper folder to changes.patch
You should then be at the same place you were on the other repo, too.
However, if both repos are equivalent, whether you commit and push your changes from the current repo or the other, they could eventually be replicated on both, so think about the necessity of moving the changes across repos. Use branches to handle different feature development.