You should look at your motherboard manual and see what it has to say about it, most modern motherboards will not support it unless specified in the manual, or they have a little +4 sticker over half of the 8 pin socket. The downfall to using a 4pin is you only have half of the current required to power it. I would recommend just buying a molex to 4 pin to supply sufficent power. http://www.amazon.com/StarTech-com-LP4P4ADAP-Auxiliary-... will work, just look at some computer shops that ship to your country.
Yeah your power supply is 80+ gold from what I read when I looked up your model. I would say use the adapter, but start saving for a power supply that has all of the necessary connectors so you can buy one within 3-6 months. The molex will be fine for a few months, but like a spare tire, I wouldn't recommend using it as a permanent fix.