you don't but what i would suggest is get your nationaldex (so you can migrate) then if you have a firered leafgreen water or electric gameboy games, then on 1 of those games i mentioned surf west from 4 island and then talk to the old man who will give yu an egg whic is a togepi, then hatch it, and migrate it with 5 other Pokemon to your diamond. then you can catch them on the pal park on route 221. good luck!
You get a togepi egg in Pokemon Platinum, not Diamond.
you can get togipi by the swarm in diamond or pearl
Togepi doesn't have a certain level for evolution; you need to have a strong bond with your Togepi, i.e. "happiness".
You can catch a wild Togepi on the island off of the Figt Area. No one will give you a togepi egg in the game.
Use Pokeradar in route 230.
You must first get Togepi on route 230 using your poke-radar. Then you must get Togepi to evolve into Togetic. Togepi is a happiness evolution, which makes sense as Togepi is a egg Pokemon.
You bring it to level 50
Leave it with the nursery
you need to hatch a togepi in soulsilver or heartgold then trade it to pokemon diamond
The shiny stone is a TOGEPI evolution stone
you use a dawn stone to get togekiss
Pal park, trading otherwise immposible. I have platinum, and when you go to eterna city cyntia gives you a togepi egg.