Cost to install HVAC/ductwork

[Suzanne B.]

I know costs vary widely.  I'd like to hear some guesses or first-hand accounts of how much it costs to install HVAC and ductwork in a house that currently only has radiator heat.  This one in particular is about 1,400 sq ft, single story, has a full basement and a full attic.  Located in the south where it gets hot, insulation is good however.