You begin with Tanya, three engineers and two GIs. Only Soviet infantry units stand in your way between here and your destination, Tanya can handle them. But, as you begin to move some cool reinforcements arrive: Rocketeers! They can fly and are pretty effective against infantry, use them to scout ahead and take care of anything that might harm your small ground unit. The base is not far away at all, and can appear intimidating but it is not very well defended. Keep your rocketeers far away from that flak cannon. It'll make short work of them.
The small lake near the base entrance is very much a vulerability that Tanya can exploit. Swim her across it, taking care to stay away from the sentry gun on the left side. Take out the infantry, then cautiously move into the base and destroy the flak cannons with C4. Once the anti-air capabilities have been eliminated use the rocketeers to destroy the sentry guns. Don't attack the rest of the base, it's about to be yours. Once the sentry guns are cleared, use your engineers to capture the buildings (more will airdrop into the base, you'll have enough to capture everything). A nice prize awaits your forces here - an fully loaded airforce command center (the harriers will vanish when you capture the building, but more will come to replace them). Don't rush to use the harriers yet, but do hotkey them. They can be useful to defend your base against enemy tanks. Another building is new to this mission - the war factory. So, now you can build grizzly battle tanks! Take a couple of moments to build two pill boxes near the base entrances. It's always a good idea to defend your base with something.
While building up your forces for an attack (at least 6 grizzly battle tanks, a dozen or more infantry) use the rocketeers to attack units outside the Soviet base (small groups of infantry, I even eliminated a tank this way) but don't stray too close. More flak cannons defend the base as well as flak half-tracks (basically mobile flak cannons). Return your rocketeers to base as they will make nice guardians if your assault on the Soviet base fails. Maneuver the attack force (with Tanya) to the north side of the Soviet base. It's very poorly defended here. Order your tanks to destroy a section of wall so Tanya can slip through. This can almost be done entirely with Tanya, but the enemy vehicles pose a threat to her so you *must* have some tanks. Let your other forces draw fire while Tanya obliterates the base. Move her from building to building, taking out infantry as she goes. Once the anti-air capabilities have been eliminated allied paratroopers will drop in. Finish off the power plants and victory is yours!