It doesn't sound like you had very much time to react. Especially on a dog that has already decided to bite. I think climbing in your Jeep was probably the best option. You have high ground and your boots could be used.
Most of my dog encounters take place at night and they are often more focused on my partner then me. I've found a bright flashlight beam to the dog's eyes and a loud Pfui (all dogs understand Dutch right?) discourages a lot. Actually any stern command works but Pfui comes naturally to my tongue.
OC doesn't effect dogs like it does people but if you spraying a fog or a cone pattern the cloud discourages them because they don't see things like we do. The cloud is a solid object to them. Fire extinguishers work on the same principle.
I've worked with an Officer who used to be in animal control. He used his extended ASP as a pole to push dogs away. He told me any pole works. I have a snare that works well for that. Snaring a dog is a lot harder than it looks.
Tasers seem to be very effective as a deterrent. They definitely don't lock dogs up but the overwhelming majority seem to decide they need to be in the next county. The wires break off but they usually have no interest in coming back.
LSDDs and beanbags are very effective against dogs if you're working in a team environment.
Did you go to the ER for the bite? They are something that really needs to be cleaned out. It's something getting water with/out antiseptic flushing a puncture. Think a big syringe with a bowl attached to it. Punctures can get nasty. Lacerations are probably easier to clean. It's something to see water going in one puncture and flowing out another.
Here's a link for dog body language.
http://www.poochpalspetcare.com/dogs-body-language/