Anything can be done but it's hard for me to believe this is a DIY project. You will need to find a way to bridge over the window with an arch or header in such a way that the load is adequately supported. Also if the wall is important to the lateral strength of the building (and an exterior solid masonry wall probably is), you need to make sure the entire opening is framed out in a way that doesn't affect the shear strength of the wall.
I see this question was asked 4 months ago (oh, and a comment added 1 month ago) so this may not matter, but the topic intrigues me. So...
Yes, there is a way to determine exactly what to do and how to determine if it will crack again. There are geotechnical engineers out there that analyze soil and sub-soil conditions. They can tell you exactly what "your" soil bearing value is and what "kind" of footing to install, (I.e.: standard spread footing, piling, etc.). However, they can't tell you how big the footings need to be...that is done by an architect or structural engineer.
They will add up all the loads in your house and decide where the loads come down on your footings and then decide if the existing footings are big enough based on the "soil conditions " provided by the Geotech Report. If they are not the right size, they can provide a design on how to fix it.
As you can imagine, this is quite expensive. An alternative to all that is to work with a REPUTABLE builder in the area and repair your walls, "fix" your footings and see how it goes. This trial and error method seems silly to me, but it probably depends on how long you're going to stay in the home.
Also, you could ask your neighbors if this occurs every year, or just once in awhile. Maybe you just repair the cracks and paint ever couple of years.
By the way, if you get the geotechnical report done, but don't follow through with the repairs, then where I live you need to disclose that when you go to sell your house. Attorneys love it when the seller does not disclose EVERYTHING.
Best Answer
You should be able to hire a structural engineer for consultation on your project. Find someone who does residential jobs. I did something similar for a remodeling project. The cost probably varies but the guy I work with is $180/hour. If you have to file a building permit you will have to do some kind of structural drawing showing the alteration and have the engineer put his seal on it indicating that he approves the plan.