yeap u need a new psu buddy. 300w isnt gonna cut pal.im surprised ur system was runing at all.
i know what you are saying to. u have the power dongle in the card then 2 open ones coming off of it and therefor u have one free and i dont think u can do that gett this power supply here or something similar and everything will fall into place.
i beleve that should do the trick.
but if it works then leave it alone! if ur card works and everything runs fine then leave it alone i dont see why u would even say anything if its working ok. but i would still get that psu for reasurence