Toxoplasmosis: igg results positive156 - (igm negative - 0, 15 with lab range of less than 0, 9 = neg). is this infection more than 4 months old ?

Probably.: The immunology results you describe are most consistent with a remote infection - should not be a problem for a current pregnancy. Talk to your maternal-fetal medicine expert for additional details in your particular case, and avoid all contact with cat litter boxes throughout your pregnancy (and beyond). Also, avoid all undercooked meat!