buffy and spike are sent back to the past

I read this story so long ago I don't even know if this is the right description, but I loved the story and want to find it but am having trouble. Spike and buffy get sent back to the past or another dimension thats in the past, buffy has amnesia and does not remember anything, so spike pretends to have her as his charge. In the beginning whistler comes to them and help sets spike up. Humans and vampires actually interact with one another, its a secret society of sorts I believe. Buffy and spike integrate into this society, but eventually get sent back to the present, and meet up with the vampires that they associated with while they were in the past.
PLEASE HELP!! would love to find this story

Sounds like Lost in Time by Spikes Kat, can be found at the website Seductive Embrace.

http://spikeskat.rogue-poet.com/seductive_fiction.htm

Could it be Lost in Time By spikeskat
?

It's at sinister attraction:

http://www.sinister-attraction.net/stories/s/lostintime.htm

Seductive Embrace. That's where it is complete!! Definitely go there instead of sinister attraction as it is not finished at the latter site. I love that story. There are a couple of other related stories at Seductive Embrace as well.

THANK YOU to both of you for the sites and the store, that is the story I am looking for and it gives me new stories to read, so thank you again.