Unfortunately - you ar e not in a very good situation.
As properties were in California - the capital gain from selling these properties is considered income from California sources and is taxable for California.
You CPA should advise you on that issue.
You do not have any choice, but to file California tax return for 2005 as a non-resident and pay income tax only on income from California sources.
As you was a resident of Oklahoma - you may claim a credit for taxes paid to California. You need to amend your 2005 tax return. Generally - there is three years statute of limitation on additional refund that will run out on April 15 2009
You need to use forms
511X - http://www.tax.ok.gov/it2007/511-X-A-W.pdf - Amended Resident Individual Income Tax Return (for tax years 2005 and prior)
511TX - http://www.tax.ok.gov/it2007/511TX-07-W.pdf - Oklahoma Credit for Tax Paid to Another State
Sorry - small correction...
you need to use form 511TX - Oklahoma Credit for Tax Paid to Another State for 2005 - http://www.tax.ok.gov/oktax/it2005/511-TX-05.pdf