Well, someone writing things based on Austen has to love it. =)
If you missed it, there was a bit of a hubub a few months ago when an Oxford professor started saying Jane Austen required heavy editing. (See here for the NPR segment with her.) Apparently if you look at Jane's actual manuscripts as she sent them in, you'll see that she had a shaky grasp of punctuation and couldn't spell worth a darn.
Well... So what? I don't enjoy her works for their comma placement or for 'i' coming before 'e' except when it shouldn't. I love her for her characters and plots.
However, that isn't to say that the errors didn't need correcting. It's hard for your genius to stand out if people are busy wondering if you know what a dictionary is. If everyone who saw her writing when it was first published had said, "Bah, she can't even spell!" and tossed it aside, then the books wouldn't have become classics and I never would have seen them.
No matter how brilliant you are, you need editing. Even when editors write books, they find other editors to work on them.
"Yes, Andy," you may be saying. "That's why publishing houses have editors."
Exactly! But you're probably thinking that means you don't need a freelance editor if you're pursuing traditional publication. And you may be right. Certainly there are a lot of horror stories about unethical freelance editors out there. And certainly the standard for getting an agent is a little lower than the standard for getting on the shelf at Barnes and Nobel. You have to look better than Austen's rough drafts, but you may be able to do it on your own.
If you have good beta readers, you can definitely try to find an agent without an editor. People succeed at it all the time. But if you're in doubt about whether your manuscript is polished enough... Well, click on the link to Cassandra's page. It costs nothing to have her look at a sample and tell you whether she thinks she can help. And, yes, I do actually trust her to be honest about it.
If you act fast, you can even enter her Year-End free edit contest, here. Though you do have to be willing to tell her what you want for the winter holiday of your choice. :)