Just amend the soil in your beds where your planting plants. For me amending soil is removing about 1/2 the dirt and mixing in aged manure. My soil is so crappy it hardly grows grass/weeds. Yet I currently have 6 healthy apple trees, 45 norway spruce, a 25x32ft garden and 10 blueberry bushes. None of this was done with a tiller or any huge machine. 75% of the work was done in the last 2yrs.
The best soil is built from the top down and where you really need good soil mix it in. Theres an art to planting in clay soil. I suggest you look into it a bit. It's not terribly hard to do.