1-I'll bring to you an umbrella No. This is not correct. You can't put a phrase ( "to you") between the verb and its direct object in this way. 2-I'll bring you an umbrella Yes. This is fine. You can insert a single-word pronoun between the verb and its direct object. 3-I'll bring an umbrella to you OK, but it's not very natural. It's not even very easy to say. The reduced vowel in 'to' means that you finish the phrase by saying 't'you', which is rather awkward. The second is the most natural sentence. Try practising it with other pronouns: "I'll bring him an umbrella", "I'll bring her an umbrella", "I'll bring them an umbrella"... and you'll see how natural it sounds.

I hear both the second and last forms often, but I think the last is best. :)