Just transpose it up a semitone.
The 'rule of seven'. means that you play the same notes as shown, but imagine the key signature shows just one sharp.


"Rule of Seven": transposing by a semitone the number of flats/sharps in the new key signature plus the number of sharps/flats in the original key = 7

Of course, if you've got the fat fingers referred to by JiK then you're more likely to use this rule to transpose from Cmaj up a semitone to C#maj (7 sharps) or down a semitone to Cb(B)maj (7 flats)