Need advice to improve climbing gearing for a road bike: 2012 Cervelo R3 kept in the French Alps. Would like to change its gearing for easier climbing.

Currently: 10 speed Shimano Dura Ace with 34/50 chainring and 11/28 cassette with Dura Ace 10 speed derailleur, and Dura Ace 10 speed shifters.

Would like to change to: 11/32 or 11/34 10 speed cassette.

Question-1: what components, besides a new chain, do I need to find? That is what type of derailleur would be compatible with 10 speed Dura Ace shifters, which would accommodate 10 speed 11/32 or even better, 11/34 cassette?

Question-2: If I change just the cassette to 10 speed 11/30 or 11/32, would it work with the current derailleur without changing it?