Hmmm i dont want to FRY mobo and others so i think i have to buy 500W PSU?
If you want to be sure that you will have no issues withe PSU, yes you want to replace your brand with a better one. You don't need a 500 watt one though, a 400 will do just fine, although the price difference won't be much at all between those.
Here is a link to a good thread about which brand you'd be OK with, look at those listed as good in your area for prices and models. http://www.tomshardware.com/forum/323296-28-best-brands