TL;dr: You will be able to do everything remotely in LoL Client via Android phones and tablets.
This app enables you to
1-) Join the queue
2-) Accept the game
3-) Select your Champion
4-) Arrange and choose your Runes, Masteries and Summoner Spells
5-) Chat with your teammates and friends during this period.
What outshines this app is that it shows LoL Client in real time, it is very easy to use and you do not need to give any of your LoL account information.
The only thing you need to do is to download a desktop application.(~350 Kbytes )
Lİnk for the Desktop Application: www.lolmobileapp.com/downloads.html