My two dogs have started fighting and I have no idea how to make them stop. What should I do?

Dear Ed,

I am going to pray you read this and answer me. I have 2 dogs that have begun fighting and we are at the end of our rope. We know we need professional help, we know that we have made the mistakes that have lead up to this. I have 4 children ages 2, 5, 9, and 12 they all love our dogs, as my husband and I do as well. We have a 4 and ? year old terrier chow mix and a 3 and1/2 year old pit boxer mix. They lived peacefully together until Jan 16, 07. That was their first fight. They were both down stairs eating, as they had done 100?s of times, and for some reason the fight began. It lasted what seems like a lifetime, fur and teeth and growling, and blood everywhere. I tried desperately to break them up, I was home alone with them and my 18 mth old and 3 year old. I screamed, I hit, I dumped water then stupidly, I bear hugged my bull and pulled her off. I KNOW HUGE, HUGE, HUGE MISTAKE. Thank god I wasn't bitten. I will be honest that after that I became terrified, not of the dogs, but of the 'FIGHT.' The noise, the ferocity terrifies me. All was then quiet until literally 1 year to the date, Jan 16th, 08 they fought again over the attention of a child friend (he is 15) that I was babysitting. Two weeks later another fight erupted over a bowl of mac n cheese on the table. That leads us to this past Monday night. My 12 yr old daughter and I gave the dogs a bath, separately, first was the bull. We put her inside then tended to our terrier mix, we clipped her and then bathed her and brushed her. We then let them both down into the back yard as usual. We have an electric invisible fence which both dogs mind Very well. Right away I sensed something amiss. My terrier was walking around and my bull was acting strange. Head down, tail down kind of slinking. They both did the smell thing, head perky kinda jumpy. I didn't like what I saw so I called my bull to me, she did come right up to me. My daughter seemed to think all was good. I then went into the yard with the animals and daughter. The black dog was on the other side of the yard poopin, my bull was sitting in front of my daughter, my black terrier walked over to them they touched noses and as my terrier went to turn my bull attacked, it was horrific. She was relentless. I screamed, I panicked, my husband came running and the only thing we had was the hose so my husband aimed and squirted. It stopped my bull long enough for my terrier to escape to the deck. The very odd thing about this is that FOR THE OTHER FIGHTS MY TERRIER WAS THE STARTER OF THE FIGHT, THIS TIME IT WAS THE BULL AND I CAN NOT FIGURE OUT WHY? They both ended up in the hospital, both needed stitches and we are left confused, frustrated, scared, annoyed and heartbroken. We believe that to take on the responsibility of owning animals you see all of it through. We know we need help, this is out of our range as to what to do. We own a camper and take our dogs camping all over the country with us, after Mon I'm terrified. If that broke out in our camper the result would be devastating. We want to keep both dogs, but realize we need to fix this pronto, start from the beginning. BUT HOW, Where?. Is this fixable? I have been reaching out for help to no avail. CAN YOU PLEASE HELP US. TELL ME WHAT WE NEED TO DO. PLEASE.

I pray you read this and can guide us, we love them both and want to do right by them and by the family.

Thank-you,
Jennifer