The parties passing the 4%-barrier:
Coalition for Bulgaria are the ex-communists and some smaller allies
SIINM is the party of the former king Simeon II
MRF is the party of the Turkish minority (now in the government too)
Attack is a new ultra-nationalist party, opposed to EU accession
UtDF is the Union of Democratic Forces, they used to be the largest right wing party (and also formed a government once or twice) before the king formed his national movement.
DSB is a splitoff of the UtDF, a bit more hardline than the UtDF (new party).
BPU is a christian democratic/agrarian party, already in parliament
So, the ex commies can't really form a government, being that the other parties are all more or less right-wing.