Oats/vetch would be a good cover crop. The best source of information for a beginner is your Co-operative Extension Service, which will have ties to UC-Davis, your land grant/ag university. Here is the lookup site for them to find the office in your county, and the phone numbers to call.
http://www.csrees.usda.gov/Extension/
Before you do too much tilling(which will be necessary) talk to your extension agent and get yourself set up for a soil test. You should also dig a straight-sided hole in your soil, and observe its texture and composition from the side walls and to see just how compacted it is, if the hardness is due to just dryness (drought) conditions, or whatever.
It's getting a bit too late here in Michigan to plant oats, since they will winterkill when it starts freezing. An alternative for you to plant--depending on your own climate, might be winter rye, which will germinate even down to freezing weather, and won't winterkill. You should probably rent a rear-tined rototiller--the best to me would be a Troy-Bilt Horse, to do a couple of passes in your new garden plot. Then you can just hand broadcast your rye or oats, so you get an approximate coverage of one seed for each space the size of a quarter. You should then use your garden rake to try to get them covered up with soil. Then you can purchase a spinner-seeder(about $30) to use for the vetch seeds., and I would sow them in two passes 180 degrees to each other--and at about the rate of one and a half times the rate recommended. Watch your seed as it sprays out to see how it covers. You may have to block the seeder slot/hole. Then gently cover those seeds with a yard rake(springtooth leaf rake) to get some soil coverage over the seeds. That's all there is to that....
Hopefully, you will get a good growth, and in the Spring, you can rent another rototiller to incorporate all that good biomass into the soil. At that point you'll be good to go on your first garden experience.....No doubt you will have a learning curve............
One place to get some good information is the "Fireside" sticky in the gardening forum. There are lots of posts there that you can study while you relax by the fireplace this winter, to increase your knowlege. Another site, is this one: a college course (no, no tests, no fees...just lectures and demos) from North Carolina State University. You might like it.
http://mediasite.online.ncsu.edu/online/Catalog/Full/f5a893e74b7c4b7980fd52dcd1ced71521
In time, you will need to know about fertility and composting, and many other ways to improve your soil and vegetables. You'll find plenty of ideas here and on the gardening forum...lots of varied opinions, too, and you will want to choose a few, modify some of them, and find out what works best for your soil and conditions. Best of luck, and, oh yes, buy a good weed hoe, and a good pair of gloves....
geo