not get rid of Syrian Government before terrorists are taken care of

After four and a half years of fighting and conflict, it's time for the war in Syria to end as peacefully as possible. However,(not taking sides), the Syrian Government cannot go just yet,(if anytime soon).
Alongside the opposing sides of the Syrian Civil War, they are also dealing with the problem of terrorists, such as ISIS and Al Nusra(Al Qaeda). The terrorist problem should be taken care of before anything happens to the government,whether or not current Syrian President Bashar Al Assad is doing what is right.
The Syrian Government has backed up and supported countries of the Middle East in many past crises, and if the government goes now, the whole Levant(Lebanon, Jordan,Palestine) will go as well. The terrorists will be able to take over if other countries can't hold their ground