Hi Vlad,
The app I recommended is for an iPad - no laptop required. If you have 3G/4G, then as described in my first post above, there is help for setting up your iPad to print to your printer via the 3G/4G connection. Also, there is help for printing from your iPad (via an iPhone) to your printer if you have no network connection on your iPad at all.
My post specifically addresses what you were asking for. You only need your iPad, the app, and a 3G/4G connection to print to your printer.
Get the app, look at the interactive Help on the app. It will give you step by step instructions for setting up your iPad to use the app to print to your printer.
Let me know if you have any other questions!
Cheers,
GB