If you value your security get a hardware random number generator -- or two
Although the RNG algoritm used in our computers is, well, pretty random its really not secure for situations where you really need it to be secure -- at best its going to be some kind of pseudo random number generator seeded with some number derived from a source like the time between two keypresses (or just the time).
Quite respectable hardware random number generators are cheap, the one I have ("TrueRNG") cost about $50 and is a USB dongle. They work on a well known principle -- differencing two random noise streams (I beleive it was the mechanism used in the original ERNIE). I'm actually surprised that we don't have them built into the architecture of every computer but then given the systematic weakening of encryption (the "accidental" choice of weak elliptic curve parameters in sample code, for example) without a lot of testing we'd neer know if the thing hadn't been compromsed either in the design or somewhere in the firmware.