Oscar, here is my Intel GPU response:
Image Insert: 19.52 KB
It's slightly better than what you have, and I was getting 40ish FPS on average. It would drop to 20ish sometime, and really heavy duty parks it hits 10-13ish area. You are probably on the edge of acceptable, but there is a demo available if you want to try before dropping the money. EDIT: Ninja'd on this with pretty much the exact same report and settings to get it smooth. Jump on in, Oscar, the water's fine.
I have a dual GPU laptop, and here is the NVIDIA GPU report for comparison for lyle.
Image Insert: 21.64 KB
This one usually runs 60+ FPS with dips into 40s and 50s and for extreme loads it will go into the low 20s. This is running default settings.