I would only get the 2nd pup when Yuriy is exactly trained how you want him to be.  (love the name by the way!!)
 
What I mean is, is Yuriy potty trained 100%?
Is there anything that Yuriy does that your trying to train him not to do?  The new pup will take after Yuriy so you want to be sure Yuriy can teach him well

.   
We are also planning on getting a 2nd this coming summer (June 2010.)  I could get the new one now b/c Snick is trained exactly how we want him to be, but I don't want to train a pup in the cold snowy winter.   
Best Wishes & Good Luck

Snick & Viv