Jack,, for lawn care service I would find a local. They will use higher quality chemicals and do a better job than the franchise guys.
Assuming you have a cool season grass in your yard you can get everything done in two apps.
For a healthy lawn fertilize in the fall. After the grass basically stops growing, you stop mowing and the grass is still green, is the time to put fertilizer down. The plant is switching from shoot growth to root growth. This is when the plant needs fertilizer. You will be enhancing the root growth without having to mow your ass off. Always use a slow release granular fertilizer, it will green up earlier in the spring and you won;t have to mow your ass off.
OK that is this falls project.
For the weed problem. Broadleaf weeds are the easiest and cheapest to control. Tri-Mec will take care of all of them. dandillions and clover are the easiest to control, but the Tri-mec will take care of all of them.
It is to late this year to apply a pre-emergent, it might help a little , but you won't get your moneys worth.
A pre-emergent is basically for crab grass, and chances are it has already germinated. YOu might not see it yet, but it's there.
The only two chemicals I would use for a pre-emergent are dimension or baracade. They both work really well.
These will both be applied as a liquid. You will not be disappointed.
GAME PLAN:
1. Have your yard sprayed with Tri-Mec, it will take care of all your broadleaf weeds.
2. This fall have it fertilized with something in a 3-1-2 ratio. A slow release 21-7-14 would be perfect.
3. Next spring have a pre-emergent applied, and spray for broadleaf weds.
4. Mow it tall. I would not mow any lower than 3 inches. The taller the plant the healthier the plant will be. Roots will be equal to the height you mow your grass at.
Good Luck, and if you have any more questions let me know.