but the aplication among offered that I prefer is Cloud LAMP server: CentOS 6.x, Apache, MySQL, PHP… How it is about Perl installation and version? I expect Perl 5.10.1 installed On CentOS

Yes, that is correct and it should be installed by default. However, be aware that CentOS (like all the RedHat-based distros) does not include all of the Core Perl modules by default and if you require these they would need to be installed via yum. Many monks will advise you to avoid using the system perl anyway but I don't necessarily agree with that. So long as your personally-installed modules (ie. not via yum) are kept separate from the system and vendor modules then they can happily coexist.

Is 1 or 2GB RAM enough for this my application? Till now maximum number of site visits was around 1000 visits in a day in the peak ...

If, as discussed previously, you perform the image-generation on a schedule and not on-demand so that essentially the webserver is just serving static content then yes, you can probably get away with the low RAM indicated. Remember to strip out all the unnecessary modules from the Apache configuration to lower the memory footprint. Sensible caching and a hybrid MPM (worker or event) would help too. 1000 visits a day should be quite achievable (so long as they don't all arrive at once).

There's no harm in using something like RRDTool just to produce graphs if that's what you want.

Best of luck with your project.