I'm 40, and my husband is 42. We're in the process of adopting from Korea. We've been waiting for about a year now (our paperwork was in Korea in June 2008), and we expect a referral sometime this fall and then we will be united as a family 4-5 mos later.
Our caseworker did tell us that we need to get cracking right after we adopt our first, if we want to adopt from Korea again, b/c their cutoff age for the father is 44 (your paperwork must be in country before he turns 44--as long as that happens, you're good; my husband will turn 43 this fall). I'm pretty sure you won't be able to adopt from China (but look into their requirements). Russia. I think, allows your ages. Possibly Guatemala, although they are still closed right now. What about Ethiopia? That's a popular country these days and one that we are considering. In terms of "can you handle it" with your ages, yes, you can! Don't let your age stop you from adopting if you think it's the right thing to do for you and your family! I love being 40 and feel younger than ever (although I wish my metabolism would reflect that!).
FYI: We are with Catholic Charities of Baltimore, and our international agency is Holt Korea:
http://www.holtinternational.org/korea/choose.shtml