There is still the katana and Uzi in the main lobby... The stairs that lead to the cafe, you can jump onto the blue sections and jump to the gun, and 'jumping off' the cafe leads to the katana.

My only advice is play by attrition: any hit is a good hit. Both of you are invincible on knock-down, so there's no point in staying close after that. & Some of your learned moves do good damage

Hey Mumu just went to a YT video to see how to do the fight. The guy took the benches and went to the statue, then hit him when he goes up, then used the pots on melee because they shield you too