How should I upgrade to an IaaS?

I was wondering how should I upgrade to an IaaS like AWS, Bluemix, Heroku, Google Cloud or Azure? Right now I have a php script who reads data from sensors and records it on mysql db. Everything is hosted on a shared hosting. I'm realizing if I host everything on my shared host, it's not scalable, because i'm already getting "Rate limit exceded" errors sometimes.

What I'm asking help for, is to understand what should externalize to an IaaS and if I should move to other db techonologies or mysql db should be enough.

I'm getting alot of confusion in my mind :(