you should carry on eating almonds because those are dense calories (as opposed to empty calories as with junk food), I'm not an expert but I think that means that your body can make good use of those calories for things such as muscle growth and energy rather than them just being stored. The fats you get from nuts are the good types of fat, as there are good types and bad types. (Saturated fats should be kept to a minimum, and trans-fats are very bad).
They are a great source of energy for workouts and also give you some protein, as well as some of the essential omega numbers. (I think these are essential amino acids that your body cannot naturally produce, corect me if I'm wrong).
Out of all the nuts, Almonds and Walnuts are supposed to be the best in terms of nutrition. Don't eat too many of them though, especially if your on a cutting diet. I personally eat about 35g - 40g every day, but should probably do more seens as I'm bulking.
As for there being an alternative, I suppose things like flax-seed oil and fish oils might be a good substitute, but I'm not sure if they have the same calorie values as almonds.