No clue how much it draws, but I doubt it's anywhere close to 200. Doesn't TDP say anything about how many watts it requires?
TDP can give you a clue about how much thermal energy needs to be dissipated for a part--a guideline for how much cooling is necessary. TDP is not going to be lower than the actual average power draw though peaks can go higher. And with overvolting and overclocking, power draw can be much more than TDP.
Given the above, let's begin:
A 2500K's TDP is 95W:
http://ark.intel.com/products/52210
According to this, the entire system draws just over 200W for a 2500K clocked at 4.6GHz, which is far higher than 4GHz and doesn't account for PSU inefficiency.
http://www.kitguru.net/components/cpu/zardon/power-consumption-fx-8150-v-i5-2500k-v-i7-2600k/ (Also, Don's bit-tech link showed the entire rig drawing 161W for the stock 2500K at load.)
Given that a mobo, RAM, fans, etc. will eat a decent amount, plus the PSU inefficiency thing, plus the fact that 4.6GHz probably means a higher voltage, PLUS the overclock, and given that at stock a 2500K's TDP is 95W, and given the bit-tech and Kitguru graphs that imply that the rest of the system is drawing something like 40W (you can actually get some good info on non-CPU/GPU power draw in this review:
http://www.bit-tech.net/hardware/pcs/2010/02/24/energy-efficient-hardware-investigated/8), I am going to guesstimate that a 2500K@4GHz will have a peak power draw of about 120W, or 10 amps on the 12V rail, for normal programs, maybe a little higher when running LinX.
And I already outlined why the 7850 is very unlikely to draw anywhere near 200W peak even with a high overclock, though if you did something crazy like 1.3 watts and 1.4GHz with liquid nitrogen or something then yeah, maybe.
Plus it's unlikely that the CPU and GPU would peak at exactly the same time so you can't just add two peaks together; realistically their combined peak will be a little less than that.
So I'd estimate that the combined peak load of a 2500K@4GHz and a 7850 at, say, 1200core/5000memory or something like that would be about 300 watts at absolute most (peak + peak, both running stuff like LinX and Furmark). Which is well within what you said your PSU could sustain on the 12V rail, though if it's a cheap PSU then they often exaggerate what their max sustained load is.