RB and LB and Trequartista are all accounted for already in the squad.
LB play Fabian Johnson. He's quality in this league.
RB play Sascha Riether, again quality in that league and in Europe.
Trequartista play Diego, and as back up play Thomas Kahlenberg. You don't have the money to spend, so use what you already have.
I played Diego as trequartista and he did magnificently. Schafer and Pekarik are more than decent fullbacks dude, why do you want to replace them? Get a CB to partner Kjaer and you're set at the back. All you need is a decent CM to play behind Diego, and partner him with Cicero. Trust, world class team right there.