mizzsocial, I think that your first step is to see your GP for early blood and urine tests and to discuss your options.
An ob/gyn is one option for peganacy care but you do have others. If you prefer a more woman centered, natural approach you could see an independant midwife or the midwives at your local hospital or if you get on well with your GP you could do shared care - where you see your GP for most of your check-ups during pregnancy and the staff at the hospital where you will give birth for the rest of your visits.
Usually once you have had your first check-up with your GP you will get a referral for your preferd model of care and you can ring them and they will tell you when they want to see you for your first appointment.