How did you enter the UK?  That is the question.  
Did you enter illegally or on a tourist visa and then apply for asylum?  If so, you'll have to apply through Islamabad.  
If you entered the UK on a work visa and then applied for asylum, that's different.  The work visa will be for at least 1 year and qualifies.
The requirements are only for the principal applicant.  So your wife (at least) is eligible to apply from the UK, providing she qualifies as a skilled worker.
You and your wife should both fill-out the online skilled worker application to see who qualifies:
http://www.cic.gc.ca/english/immigrate/skilled/assess/index.asp