If it's alternate history, your going to have to do more than just "add quadpedal mechanized units into the war along with tanks, and some weapons that several years of the time." you have to justify why these exist within said alternate timeline, or even since you seem to have a real event occurring parallel to/as your story you might want to give some reason as to why events have otherwise played out exactly as they have in this reality, sans the obvious advanced weaponry.
personally on this case i would go with real history, it's simpler to deal with personally the whole near future warfare stuff feels a little overplayed (though WWII is not exactly fresh material either so...).
I might also suggest taking the same concepts and premise (world at war, split largely into two factions, one nation having representatives of both sides as their enemies) but change the names and chronological setting to something more fitting what you want to add. your stories premise and tone stays mostly intact (assuming that there isn't a major reason for this being set specifically in uh...wherever you happen to live.) and you still get to have you fictional war machines, like having your cake and eating it to.
also, can't say i know for you homeland specifically but weren't tanks around in WWI?