Homeschool for my 1st grade and pre-school?

I have a 7 and a 4 years old boy. We just moved to this country and I am horrified at the education system here. There is no national curriculum that is encouraging and challenging and the standard is very low. I am seriously considering homeschool and had looked at several online programs. I liked the www.k12.com online school because their curriculum looks good. However, I am concerned about the socialisation as both of my children are highly sociable and love to have friends to play. Are there any homeschool group around my area, Fremont, CA that I can hookup with for the sake of my children's socialisation. Also, those experienced homeschool parents to act as my mentor and help me out when I need or maybe go on an adventure field trip together. One of my biggest fear is that I am terrible in Math and know for sure that I am not the right candidate to teach this subject. Or if there is a public or charter school that caters for homeschoolers to attend school once a week for a few hours.