At the moment I am afraid that you are correct, that the autotranslate tool is only available in Builder view.
Depending on how complex your code is, a good place to start (rather than completely recreating from scratch) is to see how much of the code you have can be implemented as code snippets in builder view (go custom>code). The auto translate may not function for specific python libraries (as it needs to know the JS equivalent). A good resource to work through any bugs you encounter whilst making this transition is the crib sheet here PsychoPy Python to Javascript crib sheet
Good luck and I hope this helps,
Becca