Your team reminds me alot of my first HG team. I had a Togetic, Ampharos, Typhlosion, Jumpluff too. (I evolved my Eevee into a Espeon) I taught my Typhlosion Earthquake, my Espeon dig, (your umbreon can learn it too)and my Togetic Extrasensory and was just fine, but the key is to hit hard before he can set up Muk. What levels are you at? If youre at level 40ish you should probably level up until your team is at least 45-50 if not more. You can get only get the TM for psychic only AFTER you beat the champion in Saffron city, and at the Celeadon city game corner for 10000 coins. But if you have the pokewalker you can get it in The Edge of the Night Sky Course.
Hope I helped! (-: