TL;DR: I want a Java program to run on a server, I want the server to forward a particular port from external to internal IP, I want store a few files on the server. Guides please.

So I made a hack job Java program that acts as a server for my android application. It stores data in text files and HTML files, uploads them via FTP to my webhost, and manages socket connections (using port forwarding) with any phones connected. Right now I'm running it on NetBeans on my home computer.

I know that it will probably slow down or crash once about 50 phones are connected at once.

Is there any way I can run this program on a server with a high bandwidth? Can someone please find me a guide for that? I'm noob and don't know where to start looking. I seriously don't know anything about renting or using servers - I need a nice guide, and recommendations.

My requirements for the server:

Can handle about 2k socket connections at once
Can run my Java code and store my txt files
Can give me a port and an IP address so TCP/IP clients can be connected 

My budget: $50 CAD per month. Please someone set my ship sailing in the right direction, I really don't know where to look for resources.