H1 - F1 transfer - Urgent! Help!

[lovely_bug]

I am currently on H1-B, but since the last two months I am without project. If I have to convert my visa into F1 when do it ? Before the fall of 2007, since the spring semester has already passed. Also, I was on H4 before converting to F1 and at that time my husband's green card was not files. But now he is in the 7th year based on I-140. Will this prevent me from getting F1.
If F1 is denied what happens - Do I become out of status even though I am be in H1-B and working on a project ? What documents do I have to show to convert from H1-B to F1.

Thanks