Practice, practice, practice.
Some skills just take time. But it sounds like you're deep in the right direction! Seek advice from any source you can get it from. Whether it be advice on stance, reaction, training simulations, or how to sweat, everyone's input can be useful (even of you determine that they're telling you what NOT to do).
My personal advice, I'll coin a US Army phrase: train as you fight. Meaning, try to simulate a home defense situation as much as possible.
Obviously, you don't want to put a bunch of bullet holes in the Sheetrock at your house, so the guy's laser suggestion is a good one. Practice timing yourself from getting out of bed all the way to taking a defensive position. Learn how long it takes to get your firearm from your safe, and know that if you just woke up, you may be groggy, have poor vision, etc. That's why repetition is important: it allows your instincts/muscle memory to take over when confusion/disorientation occurs.
Like I said, you're headed in the right direction already. Professional advice from police instructors is great, especially of you can get some personal time with them for free. If not for free, it's probably worth the time and money anyway.
Good luck, and stay armed!