you can only aspect good result if your work hard on right way and Google has not asigned any pointer just like if you get 50 backlink you will get PR3 or PR4. PR depends on many factors not only Backlinks.
iam trying to build as many back links I can , hope to see good PR in next update as it's my first SEO try
No one except google knows about the number of backlinks required to reach PR2 or any other PR. What you can do is that, you keep getting relevant backlinks, and hopefully your PR will increase.