Can I swap my engine for a better one?

While you can swap the engine you are limited to pretty much the same as the one you have unless you want to change much more than just the engine. That vehicle came with the 2.4 that you have as well as a hybrid version of the 2.4 or the 3.5 and 3.6 v6s. However, to swap to any of the other engines will also require the transmission, wiring harness, body computer, powertrain computer, exhaust system, front subframe, drivetrain and more to be replaced as well just to allow it to run and stop. Before doing all that on a car with 177,000 on it you would be better off replacing it with one that is already set up with the larger engine.
Now as to repairing the engine you have; it depends on what is actually wrong with it. Oil leaks are messy but, in most cases, can be repaired by doing a simple reseal. However, with the mileage you have I would suggest either a lower mileage used engine or a remanufactured engine. https://www.2carpros.com/articles/engine-is-leaking-oil