Tyre size will also affect the gear ratios.
I recently swapped from a 28mm Grand Sport Race to 2.3″ BSC Type1 on the Wazoo rear. I had been running 1×8 with 34/11-30 for just over a year, but the lowest gear was now too much for a local evil climb up Dell Road, which hits ~20%.
I went back to 2×8, refitting the 38T original ring, which then gave me access to the 24T granny ring again. It now means I can actively pedal down ~5% descents for longer and I now have at least three easier climbing gears compared to when I had the 28mm rear fitted.
http://sheldonbrown.com/gear-calc.html
You might find the 11-32 cassette fixes your issue, but you may need a longer cage rear mech and you may need to add two complete links to your existing chain.
But your lowest gear will be 36/32, a bit harder than the 34/32 on my road bike, that I usually need to tackle Dell Road and the brutal finish to Harvesting Lane.