If you can run 5 days a week (both physically and logistically) then great! It'd be better to run 2 days, rest 1, run 3, rest 1, rather than run 5 rest 2 (in my opinion of course).
I currently run 3-4 times a week, though usually 3, and my improvements have been fairly steady since I started. I keep meaning to build up to 5 days a week but haven't worked it out to fit in properly with the rest of my life just yet
I could only run once a week to start with - my poor joints couldn't take it - and even then only a mile (and I used to run loads as a teenager). Now I've got up to two times a week - and managed almost two miles today. It's been hard to admit to myself that I need to build up my muscles and joints, and it's been very frustrating too, but I'm determined not to let my body get the better of me, so I'm treating it kindly and I'm getting there slowly.