corel draw to Photoshop

 

Hi I have Corel 9.. I drew a map at full size 22 x 7.5  To get it to Photoshop I exported it. Saved it at 300 dpi 1 to 1. as a tif.  When I get it to Photoshop and check the image size it is 157 dpi at 14 x  3.  I need it full size at about 400 dpi as a tif.. If I kick the dpi up to 600 it gets a bit larger, do I just keep enlarging the dpi until it is the size I want?. I thought a drawing would come over as a large file.. What dpi is the drawing in Corel draw? . Am I bringing it across wrong.?.

Thanks for any help, this is to put in a book so I need a high resolution..

WPSteve