In my experience, one year is not really enough to freelance. It takes so long to get your name out and do all your marketing and all that, plus you're competing with other people, that it will generally take several years to get to the point where you can live comfortably off the proceeds.
Yes, the problem for me was that although I had six years' experience editing all kinds of things for a prestigious publishing house, I didn't have any contacts in other companies. So when my former employers didn't have any work for me, I didn't have any work. No work meant no money, and it wasn't really feasible for me to live on nothing for several years to 'get my name out there'.
On the issue of marketing, I guess it can be helpful if you're targeting authors directly. I had a couple of freelance jobs directly for authors, one of which I actually turned down once I'd seen the (bad, unsaleable) manuscript. I have never felt terribly comfortable about charging people to polish up manuscripts that have no hope of ever being picked up - it made me feel like a shark, contemplating it - so I was really after work for publishers. For that, I'm not sure how helpful marketing yourself is. When I hire a freelance editor these days, I don't go and Google for one, I ring up freelancing ex-colleagues whom I know personally, or ask my current colleagues for a recommendation.
On a side note, though, since you're planning on going into acquisitions editing, it might be useful to try for the internships instead of freelance, since it might be closer to what you want to do (though I've never worked in a publishing house, so others will be able to tell you better than I whether that's true).
If that is indeed the OP's intention, I don't believe there's any other way to do it other than starting out at the bottom rung of a trade firm. I have never met anyone in the business who was hired in to a commissioning role purely on the basis of freelance work. I have worked with a couple of Editorial Directors with no previous editorial experience, but they had come in from agenting or from high-powered book-buyer jobs.