Doggie Advice Needed

Sailor Boy and I live in an apartment, obviously. We have 3 neighbors, two across the hall and one next door. We've never actually met or seen any of these neighbors in the year we've lived here (very bizarre i know...it's not by our doing...we just never see them). Anyways, we knew getting a dog might be a little straining for our current living situation, but we figured we could make it work for a few months until we started looking for an upgrade when our lease is up in July.

Well Spencer has extreme seperation anxiety. Like, EXTREME. You can even close the door to the bathroom and take a shower without her going crazy and barking/howling like mad. Now, we know she is part beagle so she's prone to barking and being loud and we have no problems with that. But this is not normal. We need to be able to live our lives and run a few errands without her flipping out. She is in the crate all night long without a peep, happy as can be. But the second you put her in there during the day to leave for work or run errands, she's freaks. It's starting to become a big problem because if our neighbors complain, it's all over for us. We really can't risk getting evicted over the puppy (as much as I would want to pick the puppy over our apartment - which I told Sailor Boy last night and he was not amused).

She's such a wonderful fun puppy 95% of the time when you're with her. She hardly ever even barks outside of the crate and being alone. We called the foster mom she stayed with before us and she said Spencer never did this with her - she would bark for a few minutes and then quiet down. We've left toys, chewies, kong bones stuffed with peanut butter in her crate with her and nothing works. Yesterday was my day off, so I put her in the crate while I ran to the grocery store. I left quietly and then drove around to the back of our building to see if i could hear her. I sat in my car outside our building and waited - she didn't stop barking for 20 minutes. So I finally left and went to the store for about an hour. When I came back, I pulled around back again and listened - you guessed it - still barking. That's a total of almost an hour and a half of straight barking. And this barking is not just little barks...I could hear her from my car with the windows rolled up!! So i walked up to the building and came inside to the apartment. She was like freaking out when she heard me come in. I let her out and didn't say a word or make eye contact with her (that's what it said in our puppy book). We just walked straight to the door and went outside. She's still barking like crazy and jumping up on me. I turned my back to her and just stood there (another tip from the puppy book). She finally quieted down and we walked - and she turned back into her normal loving self.

What can we do??? She obviously had something happen to her when she was really young, but this is super extreme! I don't understand why she's doing this now, when she didn't do it in 2 months at the foster home. We really have to get this figured out ASAP or else our neighbors are going to kill us! So I need advice badly...if anyone is reading this and has any, please let me know. We are desperate! I'm going to call some dog trainers this afternoon to get some advice and figure out what is going on. Help!!