OK, I did some calculations

I took my NL10/PL10 winrate over 20K hands, I added half of the rake to increase my winrate to what it would have been if I had played on stars
then I multiplied my win rate and standard deviation by 2.5
I used BB/100 and std. deviation/100 figures instead of per hour, but I think as long as both are correct it shouldn't matter

I put those figures into an online risk of ruin calculator at http://www.poker-tools-online.com/riskofruin.html and got:

Risk of Ruin 0.009393%
Win Rate 2.465
Standard Deviation 17.1
Bankroll 550

This assumes that over my last 20K hands I improved enough to have the same winrate at NL25 as I did at NL10