Good morning kelly
Go to Tools > Add-Ins and select Analysis ToolPak.
Not much will seem to have happened, but you'll have a new function (amongst other things) in your arsenal called CONVERT.
If you have your kilos (1000) in A1, then this formula in A2 will return 2204.623 (pounds):
=CONVERT(A1,"g","lbm")*1000
If you want to show it in stones and pounds (and remember that this looks better but you will lose "addibility") then put this formula in A3:
=ROUND((A2/14),)&" Stones and "&ROUND(MOD(A2,14),)&" pounds"
You could take it even further to show ounces but you get the idea.
HTH
DominicB