i am getting only 2 endings

Is that 5000 before or after the multiplayer percentage?  (Example: 5000 points in War Assets but at 50% Galactic Readiness = 2500 points total, below the 2800-point minimum for the third ending.)  If not, you'll need to play a little multiplayer (2 rounds should do it) to get your Galactic Readiness up to at least 56%, which will get you past the 2800-point minimum total.

Exactly. Effective military strength is what counts.

Note that with the extended cut installed, multiplayer is no longer necessary to get access to all the endings. The values have been lowered somewhat. Still, if you don't mind playing online, it can give you a significant boost.

You can also use N7 HQ to boost your effective military strength.

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@ultraseven621 wrote:
I had not installed "extended cut DLC" and i have not played multiplayer much. 3-4 times .but failed lasted till 1-2 waves

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I tried playing multiplayer by myself, and only could get a few rounds in as well.  Pick quick join (pick Bronze difficulty level) and play with random people online - with 4 players on bronze, you should be able to get to the end pretty easily.  If you die, either another player will revive you, or you'll be in spectator mode until the end of the round, but will be automatically revived at the end of each round.  Once all rounds are complete, you'll get about 4% added to your galactic readiness.

PS: Unless you are specifically trying to see what the original ending looks like, you should download the extended cut DLC - it's free, and although I've never played the non-DLC ending, I've heard the DLC makes the ending a lot better and less confusing.

(Sorry; forgot to check this thread for a while; hopefully you found the answer in the meantime.)  You don't need friends; you can just join a session or host one; it'll pair up 4 strangers together.