It's probably better to start small and expand as you go along. Gardening in a big space might be a put off after you realize how much work / time is taking you. I would say start maybe a off 4 - 4'x4' bed and see how much you like. You can always expand if needed. But don't forget there's only the two of you! Unless you're vegetarians, I doubt you can eat all that food. I'm not sure where about you live, but first to do is find out what "zone" you're in. It basically tells you what you can grow when. http://www.garden.org/zipzone/

Unless you live in the hottest zone down in the States, tomatoes do well in full sun. Most vegetables needs at least 6 hours of sun. Lettuce and some other leafy vegetables can use less sun.

And I like to have raised beds that are about 4'x4' with about 2 feet of foot path for wheel barrows. 4' is good because you can reach in the bed without stepping in it. Ideally, you should have about 12" of good quality compost/soil. Not sure if you have access to "sea soil" down where you are. But I had some one year and everything I planted with that soil grew like crazy!

If you need more help, try http://www.gardenweb.com I learnt a lot asking people in that site. Or email me directly if you have more question Gardening is my passion