Vulcans: Their strength level varies, but I believe it is stated in DS9, "Take Me Out To The Holo Suite," Vulcans are 5 times as strong as humans. Other sources seem to indicate 3 times as strong.
*Correction: Vulcans are 3 times that of humans, according to DS9's "TMOTTHS"
Klingons: While Klingons can be agreed to be tougher than humans (redundant vital organs, train as warriors from childhood and assumed to focus on physical fitness and fighting), on average they seem to be about as strong as humans. Worf would be an exceptionally strong Klingon or human, so I am not sure he would be a good example as the average "Klingon," and there is Star Trek 3, where Kruge picks up Kirk and throws him easily, indicating superior strength. However, young Spock threw a Klingon about as far, himself. So, I think Klingon must be somewhere between a human and a Vulcan, at maybe 1-3 times the strength of a human.
*Correction: Average Klingons are probably not as strong as Vulcans, so they are likely 1-2 times as strong as humans.