Dodo (LB) Brazilian, can be had for 2.1mil US always, can start 1st season in championship then is just below premier league quality 2nd year, 3rd year starts to become dominant, 4th year 7.6 at LB in 32 starts. You can also bring in Jack Robinson on loan, I've won the league with Robinson as my starting LB in year 1.
Your squad should be able to win the championship with no additions. Gueye on loan is a good one. Try and avoid many permanent signings, loan players until next year.
Ryan Shotton at Stoke. is a nice addition if you can scrounge up the almost 9 million US it usually costs. He will be your backup RB to Demel, and also a 3rd or 4th choice CB.
Nemanja Pejcinovic at OGC Nice is a good CB who can be a PL player for a few years, he usually costs around 7.5 mil US.
I sell Carlton Cole (he is too slow for my tactics) and Matty Taylor, as well as Gary O'Neil if you can get him healthy long enough to sell (i usually cant, its horrible), and those three players can get you 10mil+. Dont forget to ask the chairman to increase transfer %.