Within the bill passing Colombia's agreement was an extension of the Andean Trade Promotion and Drug Eradication Act (ATPA or ATPDEA). The ATPDEA was extended through July 2013 and applied retroactively back to February of this year, when it expired. The retroactive effects and current implementation are designed to make sure Colombian exporters continue to receive preference, as they have for the past two decades, while the bill is implemented.
The biggest beneficiary may be Ecuador. With no trade agreement on the agenda and with bilateral relations not doing so great, Ecuador was not going to have an easy time getting its trade preferences passed through the US Congress. By piggybacking on the Colombian bill, Ecuador receives two years of trade preferences without the controversy of going through the renewal vote on their own. Whether they can get an additional renewal in 2013 is going to depend on a number of political factors within both the US and Ecuador, but for now, it's good to have their status set as the status quo.
Hypothetically, Bolivia could benefit as well. However, President George W. Bush suspended Bolivia's participation in the ATPDEA benefits in 2008 and President Barack Obama has maintained that suspension with Bolivia refusing to cooperate with US counter-drug efforts, which are a congressional requirement of this bill.