How do I beat Champion Lance in Pokemon Heart Gold?

It looks like you've only trained your starter. I'd reccomend leaving the elite four as fast as possible, and starting to actually train the gyardos and Donphan. Replace the ditto, and though I'm glad that you're supporting your types, get rid of either Ho-oh or Entei. Switch one with an electric type, that'll be good for defeating his gyarados. Give the red gyarados a TM to teach it blizzard, and then that'll be able to help you survive the champion battle, after its trained a bit.