In theory, your PSU should be ok. One of the differences between a Top quality PSU and an ordinary one is that the better PSU can deliver it's advertised power at a higher temperature(40c.). An ordinary psu may deliver it's advertised wattage only at 20c, room temperature. When you overclocked, the temperature in your case went up, and your PSU could not deliver.
There is a saying that "the bitterness of a bad product is remembered long after the sweetness of the price is forgotten". See if you can return the PSU.
The PC P&C silencer610 will do the job for you:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...