If it's low level, do what I did. Make sure you have at least one high-level Pokemon with you (I used a level 100 Gengar). Fly to Snowbelle City, then go to Route 21. Give Togepi a Soothe Bell and turn on the highest level of Befriending Power that you have unlocked. Put Togepi into the first slot on your team, then go into the first grass or flower patch you see. Wild Pokemon there are mostly level 50-52, just swap in your high-level Pokemon at the start and win the battle.
When I did it this way, I was able to get Espeon, Umbreon, and Togetic within two or three battles each.
"There's a whole lot of Internet porn out there. It's not gonna download itself!" - Dr. House