Learning conversational Japanese and grammar... Slowly

I agree with @rodrigowaick. Hello Talk is not going to teach you any grammar and if you’re not able to produce sentences on your own, it’s going to be really frustrating for both you and anyone who talks with you. Many of the people that I’ve encountered there aren’t very good at dealing with beginners so some of them may not be able to explain why they are making the corrections they are making to your messages. However, if you are able make simple sentences and understand responses from the users (in Japanese), it may be something to add to what you are doing.

As for resources, I highly recommend that you invest in a grammar book so that you can study how to formulate sentences on your own. Please check out the grammar resources mentioned on these threads (here and here). I sure you’ll find something that will work best for you.