If it has quite a bit of grass that is just overgrown, one can mow it about 3 inches in length and then overseed it with a good grade of lawn seed. Follow this with a good high nitrogen fertilizer and make sure it gets frequent watering. Continue to mow it regularly. If the patch is quite weedy, cut it fairly short... about 1 to 2 inches in length, spray with post emrgence weed killer and then water and mow as above. After about 2 weeks, follow with seeding as above. You describe an area of 3200 square feet. This should only take about 5 pounds of grass seed, which isn't expensive. Use a recommended blend for your climate. Fertilizer isn't expensive either. I don't know what you think your labor is worth, however... Good luck!