Cart store in selected customer account.
$session = Mage::getSingleton('checkout/session');
$current_quote_id = $session->getQuoteId();
$currentQuote = Mage::getModel('sales/quote')->load($current_quote_id);
$currentQuoteItem = $currentQuote->getAllItems();
$newQuote = Mage::getModel('sales/quote');
$newQuote->assignCustomer($customer);
$newQuote->addItem($currentQuoteItem);
$newQuote->setQuote($newQuote);
$newQuote->collectTotals()->save();
$newQuote = Mage::getModel('sales/quote'); => Not Load
$newQuote = Mage::getSingleton('sales/quote'); => Not Load
How to Load this model ?