Help with upgrades leveling abilities

So what I have so far, is an ability that increases attack speed on a unit, but you need to research something first in order to get that ability (just like you need to research something before you get defend). I got that down, and know how to do that, but how do you make it so that when you research the upgrade again, that it'll increase the level of the ability to level 2, and then one more upgrade to level 3?

Here i made a demo, check it out if thats what you want, and if you don't understand in the map how i did it pm me and ill explain you

I see what I did wrong, I didn't allow the huntress to use the upgrade. I feel dumb... hahaha. Thanks for the help anyways.