Google exports pagerank every 3 or 4 months in general.
It is therefore impossible to know the value of your pagerank in real-time.
To be able to see the results of your netlinking work, you often have to wait. However, it is important to keep in mind that the quantity of links is not necessarily what matters. Indeed, the links are weighted. As a consequence, 1 link can be more powerful than hundreds of other links.
Finally, the more you will climb up the pagerank, the harder it will be to gain a point, as the scale is logarithmic.