http://img190.imageshack.us/gal.php?g=gar5.jpg

Looking at your pictures, any restoration might involve a compete gut and re-do job. First thing I'd decide is if there is anything worth saving; and if there is, how can it be separated out from all that is not? Those yellow/orange daylilies might be the dreaded "ditch lilies" which are extremely invasive with a murderous root system. Regardless of how much digging you do they always seem to return. Seems to be a gladiolus or two - but they're inexpensive. Beyond that, I can't tell. I'd get in there with a sharp shovel, pry up everything possible, shake off the dirt and discard. Or, get up what you can and use Round Up on the rest - safe and effective if used according to the label instructions; and it works on the plant material, does not linger in or on your soil.

The best defense against a weedy lawn is a healthy lawn - a topdress of compost or a spring and fall treatment with alfalfa meal pellets (available at feed + grain type places, maybe $11 for a 50# bag) helps strengthen and fill in existing grass, crowding out weeds. Or, alternately, a weedy lawn is often quite green and passable looking if kept mowed.