You need defensive cover like the panda said, don't go for barzagli though. On 08 he was probably the best CB in the game but he is'nt quite as good on this one. Try Sakho from PSG, he's young and will provide cover at CB / LB for 1st season and will be able to step up to 1st team football next year.
Also you need a DM!! I'd personally go for Palombo, you can pick him up for £11m. make sure you get a very good defensive DM, not a creative one as you already have fabregas. I kno palombo has 19 creativity but he is also 20 tackling, etc. All im saying is someone like pirlo won't do cos he's too similar to fabregas, you will need a more gattuso type DM and palombo fits the bill perfectly.
If you prefer younger players, I. Camacho would also fit the bill, however he is more expensive than palombo.
Also you need a new GK. have a look at Asenjo, akinfeev and mandanda. Asenjo being the cheapest at bout £8m ish!!