401K Question: Thinking of more international investment

[phillydilly]

I have limited confidence in the future of the US economy, and have roughly half my 401k in the following 3 mutual funds (only international funds offered by 401k):
RS Emerging Markets
Janus Advisor International Growth
Delaware VIP Emerging Markets
The rest is spread between misc large, mid, and small cap growth funds investing in the US market. I'm considering increasing this to 66% or even 75% in the international funds.
I'm 28 years old and have roughly 36k in my 401k right now. I'm contributing $112 a week and my company matches 25%
Is this too much to have in overseas funds? Is my current 50% too much?