By default ACS only keeps 14 days worth of data, you will need to dump your data to another DB Server that has a truck load of storage for long term storage. You will probably need to invest in software that helps with keeping up with the ACS data, see Secure Advantage/ Frysoft for that software, as it is a speciality niche, it will have to be purchased.
Very Strong Suggestion. Have a Dev and test VMs with a standalone SCOM installation, something that MPs can be tested on so that you know what does and does not work. It is easy to do, but hard to keep up with, but necessary when you have to test something and do not want to break production. In the past I have done work for clients that IGNORED common sense in having some kind of Test or Dev system, and it always caused them problems.
Good luck