So, here is a guess, using the UK to be all of Europe (it's not) and using previous vgcharts numbers to use a benchmark, though not entirely acurate. So, if the UK is all of Europe, here are the numbers from SR2 versus SR3, estimating a 43% increase in sales.
SR2 first week sales x360: 147,246 ps3: 89,150 Total: 236,396
So if we add 43% to that, we get 338,046.
Add in the fact that it is selling VERY well in Japan, unlike SR2, and it could be Sr3 is a good hit across the world - if UK numbers reflect the rest of Europe, that is.