help hcg

I'm planning on taking hcg 2x 250 IU's a week during my 12 week cycle of test and dbol. After reading I've learned that HCG will only last 28 days after mixed and stored in a refrigerator. I have 5000IU's and b12 how do I make the HCG last my whole cycle? PLEASE HELP, I CANNOT FIND ANYTHING...