6-8 weeks. Your body should technically be healed from the surgery in 6-8 weeks. Make sure you have emotionally and spiritually healed from your loss, which usually takes longer. Some research shows that spacing your pregnancies out to 2-3 years is better for the mother and child. That may not be practical in situations of loss or older prospective moms.
Several answers. We usually think it takes about 6 weeks to complete the postpartum time to normal. So, then you could try again. Some studies suggest that waiting a year may improve the pregnancy outcome but if you are older, then your fertility is lower. I have just given you a range of 6 wks to 1 year. I suggest a discussion with your physician to decide what time works best for you. Sorry about loss :(.