Converting crankset from 28-38-48 to 30-39-53
You will need to purchase only 4 items to accomplish this swap:


Crankset - Standard road triple 
Flat bar road shifter set ST-443
FD-443 front derailleur
Possibly new cables, if they don't come with the shifters.
A new chain designed for the number of gears in your cassette. 


You will also need to ensure that you've enough adjustment range on the frame to move your front derailleur up by up to 2cm, and that the derailleur you purchase is dual pull, so that you don't need a pull converter. 

But it seems to me you've already worked that out.