My ex will need to file a amendment cause we entered dependents wrong. won't accept mine due to his being wrong. What should I do to get mine to be accepted?

If the dependent information was entered incorrectly on your ex's return, they will want to amend their tax return. You will either want to print, sign and mail your tax return or file for an extension so that you can e-file when their amended tax return is processed. 

Should I mail mine in now or wait?

You can mail it in now.