Suppose my website's home page www.easydestination.net is getting 1000 backlinks from PR 7 website. Would it only improve PR of my home page or will also benefit inner pages with PR and better search rankings.
You need backlinks from multiple website; your 1000 backlinks from the PR 7 site only really count as one. Start branching out and getting links from multiple domains. My signature link shows you how to get a link from a PR 10 site.