If you want to try a more direct approach, you would have to ignore the building and keep moving left. Next, you would have to lean out carefully. There would be a car coming this way. You would have to kill the gunner (#1) and the rest of the crew (#2), including the driver. It shouldn't be too difficult.
I assume that you have taken care of the first group of rebel soldiers. The second group will be occupying a nearby square. If you take a closer look at the first screen (#1), you should notice that you will be able to surprise them. You could also remain here and wait for them to reveal their positions (#2). The choice is yours. Just make sure that the enemy soldiers have been killed. Once this is done, you will receive a radio transmission. Gather the entire team around your current position.
2) Reach Allied reinforcements
Now you will have to reach the northern sector of this map (#1), because that's where you'll team up with allied forces. This is going to be a long and a very difficult walk, so get ready. You will have to be alerted to all kinds of possible threats. Start moving towards your new destination. Your team should hide behind a nearby pick-up truck (#2).
Get ready. You should be able to spot a small patrol. It's heading your way. You will have to kill these soldiers (#1) in order to be able to move on. It shouldn't be too hard. You could also allow your sniper to deal with this problem, however he should be standing near a good cover. Once the area is clear, start moving (with the entire team) to the north (#2). You shouldn't encounter any additional hostiles here, so you may speed up a little.
You will have to reach the upper section of this road. This is where you'll start moving east (#1). Get ready, because this area will probably be lightly guarded. You will also notice an enemy gunship in the area (#2), however you won't have to attack it, so ignore the helicopter and keep heading towards your current goal area.
I would recommend that you order your squad members to hide behind a large van (#1). You could also send them to a nearby car, however they would be more exposed to enemy fire there. You, on the other hand, should be standing near one of the northern buildings (#2). This will allow you to surprise a few rebel units which are coming this way.
You will have to kill at least three enemy soldiers. Two of them are probably heading your way (#1), so it should be fairly easy. If you're hiding behind one of the northern buildings, you will be able to surprise them. The final opponent is probably standing behind a nearby van (#2) or he can be hiding somewhere else. Either way, you must hunt him down. Once he's gone, head down to a small passageway which should be located to the north. SAVE your game, because you'll participate in some very challenging battles here!
Start moving SLOWLY towards a nearby road. The rest of the team should be following your lead. You will have to be very precise here, so you don't end up getting shot. The first group of enemy soldiers will be located to your left. You can't reach them directly, but you will be able to kill them from here. Be careful, though. One of the rebel soldiers may be lurking in the shadows (#1). His colleagues are standing to your left (#2).