I went ahead and put the numbers in myself.
Your Ibex Corrida ST has the following specs:
Truvative ISO-Flow Triple with chainrings: 48 38 28
Cassette Sram PG-850 with sprockets 11 - 32
Tire size 700 x 28 - 622
170 mm cranklenght (Best guess)
Same setup with the Nexus 8 hub with a 18 tooth sprocket
If you use an 18 tooth sprocket the gearing is almost identical as you have now. You could use a 19 tooth to make the gearing a little lighter.
Here are the gear inches for both: