Drof's right, Tim. It's a long haul. My advice is to get Thumar as good as you can make it, as a whole novel, using help from here and anywhere else you can get it. During that time, keep putting away a few dollars a month (the ones you might be planning on spending on an editor now). By the time you have the book hammered into shape you might find you've enough to pay for one of the really excellent editors that frequent Chrons to look at the whole novel.
It will be much cheaper and more productive in the long run, because the less polishing an editor has to do, the less time they'll have to spend and the less it will cost you. Advice on here is free.
I don't know what age you are (and I'm not asking!), but I started writing at 49. I submitted my first novel to publishers after less than 4 months - got rejected, obviously - then a wonderful person
@Jo Zebedee) found me, picked me up, dusted me off, and pointed me at Chrons. It didn't take many critiques on here for me to reach the stage you're at now. The 'OMG this is going to take forever' stage. I'm 51 now and the novel still isn't ready to sub (although I succumbed to temptation and put it into the Hodderscape open thingy). I feel I'm running out of time. At my age, how many novels do I have left in me?
I suspect you're a fair bit younger than me. Comfort yourself with the thought that you at least have time left to you to do this well.
It's worth it in the long run, believe me. If and when you publish, by whatever route, you'll have a novel you can be really proud of.