Hi there,

I am sending a link to a fact sheet from Penn State that is one of the most comprehensive discussions of herbicides that I've seen.  It includes the trade names of products that contain the chemicals mentioned below: http://plantscience.psu.edu/research/centers/turf/extension/factsheets/weed-management/chemical-weed...

To focus on the two weeds you mentioned, these are the pertinent paragraphs:

For crabgrass, the stage of growth is important, as you will read:

Fenoxaprop-p-ethyl is a postemergence herbicide that is slowly translocated within the plant. It can effectively control tillered crabgrass with a single application. It is relatively safe on cool-season turfgrasses but may injure some Kentucky bluegrass cultivars, especially at high temperatures early in the season. It should not be applied if cool-season turfs show signs of drought stress. Fenoxaprop-p-ethyl is less effective when tank-mixed with phenoxy-type herbicides such as 2,4-D and MCPP.

Dithiopyr acts as a preemergence and postemergence herbicide. It provides postemergence control of crabgrass only up to the one-tiller stage of development, but it can be combined with fenoxaprop-p-ethyl when two or more tillers are present.

Quinclorac is a postemergence herbicide effective in controlling crabgrass and some broadleaf weeds. Optimum control of crabgrass is achieved when quinclorac is applied before development of the second tiller or when crabgrass plants have five or more tillers. In some cases, quinclorac does not provide complete control of crabgrass at the two-, three-, and four-tiller stages of development. In these situations, a second application may be required for complete control. Quinclorac can be mixed with other herbicides, including pendimethalin and phenoxy herbicides, to improve weed control. For best results, apply quinclorac in combination with a methylated seed oil according to directions on the label.

Because nutsedge is a perennial grass weed, a selective herbicide will not control it. You'll have to choose one that is non-selective -- in other words, it will kill all grass. So proceed with caution:
A common perennial grasslike weed, yellow nutsedge, can be removed selectively from turf with the herbicides halosulfuron (Sedgehammer™) or bentazon (Basagran™). Be sure to follow label directions and note restrictions for nontolerant species.

Now that I've found this fact sheet, I'll have tor read it carefully to find out what to use on my own lawn that has turned into a mess this year!

Best of luck with yours.