yeah, try a pair of 700x28 tires on that, dropping the inflation pressure accordingly. if you get good quality high thread count tires, they ride just as fast as the skinny things but with a much better ride... a riser stem could bring those bars up 3 or 4" and maybe a little closer.
I'd skip the suspension seat post, those are pretty much awful. a milder, more touring oriented seat, like a Specialized Milano would probably help.
that does look like its setup as a 'tri' bike, and those tend to be short wheelbase and harsh, optimized for sprint racing.
but, what the other guys said, your best bet is to sell the bike locally, and then buy what you want.