Server RAM to run a 24 GB MSSQL Database more efficiently

Our client runs Sage 300 ERP Version 2012 on SQL Server. The database has now hit 24 GB and the response time of reports has become slow with some of the customized reports timing out. The client has requested me to give them specification of a server. What is the best RAM and Processor can I recommend for them. I can fore see the database reaching 40 GB quite soon. All responses will be appreciated.