You haven't asked her, "I know we had a heated discussion. I haven't heard back from you on my calls and e-mails. Let's talk it through. I value you as a friend, so let's work out being friends--regardless of how the kids interact with each other."
That last part, of course, you should say only if it's true. Hard to tell from your post. Do you like her as an individual? Would you two be friends if your children had not brought you together? Do you and she share any common interests or a common sense of humor or backgrounds that made you "click"? Do you enjoy spending time with just her and you, with no kids in the mix? Or is it really, at the root, just about getting together because the kids are also getting together?
I see a lot of posts from moms with problems with mom-friends. And I wonder if these friends are really only friends because their kids pulled them into each others' orbits. If you like HER and miss her (I mean, miss her personally, not just miss having another adult around), then work it out and communicate, rather than posting here -- talk to her. Get together with her without the kids there (this is what dads are for--partly!).
If your kids can't get along well, they are close to kindergarten age. That will pull them into other social circles. When that happens, will you miss her? Will you want to spend your own, kid-free time with this friend or not? Kids can help create nice temporary mom-pals but kids do not help make real adult friendships that last.