I cannot catch a F***ing Blitzle?

I have been all up and down route three, first of all I run into more lillipups than blitzles, and when I finally effing find one I cannot catch the damn thing. I used six great , five poke, two heal and an ultra ball on a level 12 with low yellow health (I didn't want to kill it) And the stupid thing wouldn't have it. What do I do? I don't have any pokemon with status effecting moves except leer, which I used and it didn't work. I used it until it was no good any more. I'm only in the beginning of the game and I've sunk a ton of money into trying to get one of these #$%^&* that I just want to kill now. Help.