Which apps do you need to run?
There are Windows emulators out there, but I've heard that they're kinda sluggish and slow.
If you need to run Windows programs, you need a windows machine. Emulation is too unreliable for a mission-critical application.
(I'm suprised Dell allowed themselves to get out of stock on Pentium-M processors. You should call them and see if they'll take $$ off the top.)
To some extent that is inevitable. There is an extra layer between the hardware and the software, increasing the execution time.