I made a small XL spreadsheet table for you, right next to my sprocket size calculator. Beware the size of a bigger sprocket. You'll see that the 44t is about 7" diameter, while a 60t is almost 10" diameter. Make sure you have the space/chain clearance before proceeding!
As said previously you will probably pick up some RPMs, but the table on the left assumes the same RPM as the one you got 30mph with.