Digital BW, The Print

I have a B&W digital file of a B&W photo scanned at 1600dpi at 2 1/4x 
2 1/4, then enlarged with genuine fractals. The file ends up being an 
RGB file and is 10"x10" at 360 dpi. The file size is about 45 megs. I 
usually print with my 1280 using Piezotone selenium inks and get 
great results. However, now I need a print larger than I can make on 
my 1280. Can I rez up to 20x20 using genuine fractals and get a print 
of equal quality? Which of the 2 printers, (Lambda laser or Kodak led 
printer) will give me the best nuetral print that will closely match 
teh prints I'm now making? How many Dpi should I give the lab?

Thanks in advance for your opinions.

Barry Wolf