You can always use a comand prompt (cheat), hold Ctrl+Shift+C then type in freerealestate and press enter. That'll let you move any sim into any lot, I always use that to move sims in I'm not sure if you need testingcheats enabled though (testingcheats are always enabled in my game ).
EDIT: Yes I am an idiot!!!!!!
Disclaimer: These are the personally, personal opinions of me, myself and I. Yours may vary. Terms & conditions do not apply
thank you both for the answers! I tried to go into the house to get rid of some things but it crashes, so there must be something wrong with the house. I use testingcheats too, and usually use familyFunds to be able to afford them, but the freerealestate sounds a whole lot better! Problem is I tried it and it didn't work just now before the last crash. Sometimes when I put it in it will work fine, sometimes I'll be able to change relationship bars but not skill bars, or vice versa, and sometimes it doesn't work at all.
xmirellax, is this a house that comes loaded with the game, or one that you downloaded from a CC site? If it comes with the game, opening it shouldn't cause a crash unless the game is glitching. If it's a downloaded house then yes, there's probably something in the house that won't work with your game. Go back where you got it and see if it was made using EPs you don't have or if it has custom content in it.
You might better go over to the Game Help FAQ and work through that, figuring out where your problem lies; if that doesn't solve it, then you'll have enough information to phrase your question to get good answers. Good luck.