Hi,

The distance between Okhla and Galgotias University is about 30 kilometres and you have to change two metro lines to reach there- blue and aqua line. The cost would be around 60 rupees for one way. You have to catch metro from Botanical Garden and go to Knowledge Park metro station by interchanging at Noida Sector 52 in between. 

There are also buses of the university plying in the city. So you could also check with their route.