1. More is better ofc, with dual you should be fine since server is not rly processor based.
2. DDR3 recommender, at least 3/4GB.
3. Ovh or any reseller of them.
With 2GB I'm not rly sure if you can run it.. Count 1GB for OS and applications, and depending of the pack and configs server usage is like, let's say 200mo - 1GB :)
You can decrease Xmx, but if you set it too low server won't load, else you disable most of the configs, you can try :)