Where can I get a SOVK bolt?

In general, playful pens bring entertainment to life.
It seemed to me that it would not hurt to change the thermal paste under the cooler of the video card. ASUS R9 290DCII because it warmed up under the test up to 82 ° C
Well, since the screwdriver, which I usually poke around, I had to look for, I took a screwdriver to tighten the bolts ...
In general, the slots of one bolt were rounded to zero ... (they turned out to be so delicate)
I unscrewed the bolt with an impact screwdriver and now I think where to find a replacement? In what stores are such small bolts found?
Do not buy a new CO for one bolt ?!