RHulsmeyer - you don't need Scotts, but they'll work if you want to blow the money on them and dump chemicals in your yard.
This website keeps it simple and chemical free - I like it and it works:
Basically make sure the soil is good, supplement with compost if needed. Mow high to help the grass compete with weeds.
Your sense of timing is good. In August or September (after the summer heat fades, before the fall rains), rake out the yard, clear big patches of weeds, topdress poor areas with compost, and overseed with a good local sun/shade mix. I like Hart brand seeds, you might find them in hardware stores. Keep things watered, hopefully the fall rains will help.
Next year, repeat the above steps. Do that and you will have a good lawn in a year or two.
Check to see if you have grubs. An application of milky spore in August will help keep the grubs (larvae of japanese beetles) in check.
Also keep in mind that your lawn turning brown in this heat is A-OK. It is going dormant to stay alive in drought conditions. It isn't dead. It will likely pop back in the fall when it gets some rain. If you just have to have a green lawn all year then you have to pay to water. I let it go dormant and let Nature take care of the watering, except when trying to establish seed. Then it is important to keep the soil moist.