G’day

I’m currently interested in buying a keyboard/synthesizer for electronic music production. I am currently using Fl Studio software and mainly using the Sylenth digital synthesizer and I am sick of using my QWERTY keyboard for playing keys. Before I look into purchase I would like to find out some information:

1.
I am using a new standard desktop pc computer, what possible upgrades will I have to check to be able to run a synth smoothly?

2.
Will the analogue controls work in conjunction with a different digital synth plugin, partly or not at all?

3.
Where would you recommend finding the cheapest price on synths and keyboards?

Cheers Sean