HELP! My front lawn is being attacked by WEEDS!?

My front lawn in under attack! Many different types of weeds are overrunning the whole front yard. I even have some weird grass growing there too. I cut it and it still grows back. I put some SCOTTS weed killer and watered it for a week straight and still the weeds persist. I don't want to have to call a gardner and want to do it myself. Obviously, I don't have a green thumb, so what can I do? Any home remedies or suggestions are appreciated.