The Query Letter

So I've actually been working on the novel here and there, and I've been seeing things that need to be changed, expanded upon, improved upon. I was thinking I would not send out anymore query letters until I fixed it up and bulked it up some more, but perhaps I will still send out the letter at least- after I have added to the story.
The first thing that is wrong with my query letter is that it reveals that my novel is only 70k (and I'm not even there yet). It should be at least 80k, and although I thought about simply changing the word count in the letter while still working toward actually getting there, I figured I better not. At 75k I could stretch the truth and say 80k, but not now because suppose someone bites at the line and says: "Sounds interesting, send me the full manuscript." Yes, it is unlikely, in fact, they're more likely to say: "Sounds interesting, send me the first 50 pages" which I can do. But say in the unlikelihood someone wants the whole thing- could I spit out an additional 15k words in a super short period of time? I could do it over three days, but would those words be good ones? Would they fit with the rest of the words? Would those words help the story or hurt it?
It's too risky at this point. I need to make the improvements I need to make, add what I need to add, format where I need to format before I send out more queries. When the story is actually complete and I feel the way I'm supposed to feel about it and I know it better, I could probably write an even better query letter.