Staying in the Premier League

I've just got promoted to the Premier League with Sheffield United in my first season, and I want to make sure I stay there. Can anyone recommend some good players? I've looked at players like Keirrison, Saivet and Sanchez but I'm not sure they'll give me the experience I need. I already have Guilherme and Douglas Costa. There's no limits to spending. Any ideas?

Here's the current team at it's strongest:
Kenny, Halford, Berra, Kilgallon,David Murphy, Larsson, Wagner, Harper, Ledley, Doyle, Pozzi.
Subs: Haber, Morgan, Douglas Costa, Montgomery, Guilherme, Henderson.
other players: McSheffrey, Naysmith, Sun Ji Hi.

BTW - Claudio Pizarro joining.

To stay up you need to have a strong backline. Preventing goals is key. A good blend of young and old players is also a good thing to have.

Richard Stearman, who starts at Wolves would be a good signing, as he can cover right back and centreback and is also a good player, with tonnes of potential.

Check out The "Big" teams reserves squads, as from Spurs I was able to purchase Aaron Lennon who was an absolute steal. Man City also have a few decent players in their reserves.

Tom Soares is a brilliant midfielder. dont think he would cost too much either.

Also look at the Rangers and Celtic squads, as they have some very good players who would jump at the move to the Premiership and wouldnt cost a lot of money.
Aiden Mcgeady for example.