Hi!
I can make the system but it will be a little over your budget, sorry for that.
The system will load the web page from the distributor, parse it and load a database with the data.
There will be a numerical analysis to calculate the minimal, max, average, maybe a median two.
The data can be stored for 30 days or more, it's your call on that.
I will need more information on the graphs you want, like what you want to compare since the graph in the attached png is too small to read the legend, but on the project run we can determine that for sure.
As a plus for the project, I'm also from Brazil and communication will be easier for us in portuguese, only bidding here in english for coherence with the project brief.
Any doubts just ask.
Thanks for reading,
Vinicius