Since you are certain that you will qualify for the credit, you can file an extension now and file your taxes later.
You do not have to send in the amount due with the extension.
Let me know if you have any question.
Please note: This advice is provided with the understanding that all the relevant facts have been provided by you. Any change in facts might affect the advice given and hence may not be relied on in such cases. Nothing contained in this reply was intended or written to be used, can be used by any taxpayer, or may be relied upon or used by any taxpayer for the purposes of avoiding penalties that may be imposed on the taxpayer under the Internal Revenue Code of 1986, as amended.
Yes, you can claim it in 2008.
here is alink answering most of the questions-