Perform off page seo works like article submission, web link submission, forum posting, social bookmarking with unique contents. Sure this will makes you to get a cool page rank as earlier.
I am afraid to say they are no short cuts ... you need to work intensively on link building strategy which involves: 1. Link exchange 2. Forum posting 3. blog commenting 4. article submission 5. directory submission 6. from sites like Yahoo answers and wiki .. 7. social bookmarking 8. web 2.0 profile creation 9 . search engine submission
Create backlinks using the offpage techniques of Web Directory Submission in order to increase the Page Rank of your website.
Yeah I would say get a link from another high pr site, from their homepage. It is more of a vanity thing though, because long term if you want to rank for anything competitive you are going to need more than just 1 high pr backlink