I don't read soil tests, but I know who does. Please write to me from my member page and I'll hook you up. It's all free from here on out...the analysis is anyway.

Timing:
For conventional (chemical) fertilizer like you might get from Lesco, the general rule of thumb is apply once in the late spring and twice in the fall. Don't apply in the summer because the grass is already stressed from heat and dry soils. Read the bag carefully for application instructions and settings. The guy who reads the test will help you pick a fert and preemergent...or someone else might come along here to help you.

For grain type organic fertilizers (like you get at the feed store, e.g. corn meal or alfalfa pellets/rabbit food), then you can apply any day of the year, or every day or the year if you have that budget. The application rate is 20 pounds per 1,000 square feet.

Weeds:
Your problem with crabgrass and weeds is caused by a couple factors. If you water too frequently then the crabgrass seed will germinate just like grass seed does. The other factor is shade on the soil. If you mow too short or if your grass is a thin-ish fescue, then that will allow sunlight on the soil between the grass plants and crabgrass can get started. But if you allow the soil to dry out completely between watering, and if your grass is fairly dense/tall, then you should not have weeds. Weeds have almost nothing to do with fertilizer or even preem applications. If you know you have thin turf coming out of winter, then you need to use a preem. If your grass is fairly dense/tall and you don't water every day (or 3), then you should not have a weed problem. Yes I should have been redundant in the last few sentences. I wasn't sure if it was more clear one way or the other. Water deeply and no more often than once per week, making sure the soil is fairly dry on top when you water again, and the weed pressure will drop off considerably.