We use the bare infinitive after help when the sentence is active.
Before I go to school every day, I help my mother clean the house.
(help + bare infinitive when active)
Your first sentence is correct:
"I'm looking for someone who can help me translate my webpage."
Your second sentence is not correct. Look at it this way:
Is there anyone who can help me cleaning the car?
In British English, it is common to use to + infinitive after help, but it can be dropped. See Eastwood's Oxford Guide to English Grammar (1994) p. 149:
After help we can leave out to. We all helped (to) put up the tent.