Your position certainly isn't bad. I'd say you can definitely get more aero on that bike, it's just a matter of if your body can handle it (it will take time to adjust of course).

- Lowering the front end is a good start, either with fewer spacers or flipping that stem.
- Getting your head tucked down lower and out of the wind.

That's all free and will take some testing. When it comes to spending $$$ then...

- A better cycling / tri style top, doesn't need to be much tighter but it will be smoother with less flap/wrinkle.
- I can't tell what tyres you're using, but some faster ones paired with Latex tubes may net some additional speed.
- Expensive, but some deeper section wheels.
- An aero helmet will net some savings, but I'd put it low on the list.

There's a bunch of other stuff as well and the rabbit hole is endless, but that's a very good starting point! 😀