There's an old story that goes something like this:
Little Timmy is very late to school one morning. It's 10:30, and the teacher looks out the classroom window and sees Timmy just getting into the schoolyard. He's pushing his bicycle and looks very hot and out of breath. When he gets into the classroom, the teacher says:
"Timmy, why are you so late to school?"
Timmy replies, "Sorry teacher, I had to push my bicycle all the way here."
The teacher, confused, says, "Why didn't you ride your bicycle?"
Timmy replies, "Teacher, I was running so late this morning that I didn't have time to get on the bike."
I hear this kind argument all the time when people put off automating. "I have too much to do," they say. "When this release settles down, I'll have time then."
Folks, I hate to say it like this, but you're never going to have that perfect moment where you do nothing but automate. If you're a tester, then there's always something that will need testing. You have to find ways to work automation development in to your regular day. If automation is something that you throw to the back burner every time your workload heats up, you'll never get any benefits from automation.
Sometimes this means explaining to your manager that automation can't be a side project and should be focused on sooner rather than later. Sometimes it means recruiting a developer to help get you jumpstarted, so you can get a test framework built up quicker. Sometimes it means hiring another person whose primary responsibility will be test automation.
Point is, if you're always waiting for that perfect moment, you'll never get anything automated. So do *something*. Even if it's just a small test to start with, that's something you can build on. You won't get a comprehensive set of automated tests overnight; so get one test automated/one helpful tool written and then add to that. Even if you only automate one new test a week, over the course of a month, that's 4 tests you don't have to run by hand. Or, if you're trying to build a tool that will augment manual testing, get that to your testers as soon as it can do something useful, then continue adding features. The time savings will get more and more significant as you go along.
So, long story short, just get on the bike!