Merlin summed it up nicely and I will add to it.
The Rams need three new starters. C, OG, and RT. I know am nearly alone in this camp but Barksdale's pass protection was not there last year and I am not going to blame that on the RG like some have done, but that's just IMO.
Both draft and FA, but I also think it would be wise to bring in at least one very good FA starter and another starter or BU. Can't rely on all young guys learning especially since the Rams need to start winning and get into the playoffs this year. Laurinatis, Long, and others are not getting any younger. As long as Lupati is healthy I would absolutely, no question, throw bucks at him and sign him. The Rams desperately need someone of his caliber bad. I know some of the FA signings on OL did not pan out but you don't just give up signing OL FA.
The Rams also need to draft OL rounds 1, 2, and 3, a maybe even 5. I would be comfortable only if the Rams draft OL 1,2,3 and signed 2 FA at the very least.