That is it , how much water should I have used ? I used what the HB store said 2.5 gallons and he said the hops have to be boiled 45 min boil?
If the recipe is for 2.5 gallons of beer, that's the end volume. Depending on your kettle size and heat source, you can boil pretty much any volume you're comfortable with, between 1.5 and 3 gallons.* During the 45' boil you'd probably evaporate (boil off) half a gallon of water. So you'll end up with a volume between 1 and 2.5 gallons of wort.
If you come up short on volume after the boil (intentionally or not), you can top up in the fermenter with water to the 2.5 gallon level. All good.
LME yields 37 points of gravity per pound per gallon (ppg).
3.3# * 37 = 122 points / 2.5 gallons = 48 points. That translates in a (specific) gravity of 1.048 in the fermenter.
That is, as long as you don't spill or waste any good wort. For example, by leaving much behind in the kettle. Especially with extract and average hop amounts you can pretty much dump the whole kettle volume into the fermenter, many do. No wort left behind. Then top up to your batch volume with clean water.
* Boiling smaller volumes will reduce hop utilization (extraction and bittering). So does higher wort gravities.
That's one reason to add only half or less of your extract at the beginning of the boil, and add the balance at flameout.
If at all, malt extract only needs to be pasteurized, really does not have to be boiled. It was boiled already at the malster. And then some.
The longer hops are boiled the more bitterness they yield, sacrificing their flavor and aroma. But after boiling for 5-10' diminishing returns set in, and doubling boil time does not double bitterness. After a 30-45' boil most (~70-80%) of the maximum bitterness potential has been achieved.
