Kelly Clarkson’s split from Brandon Blackstock may cost her — $436,000 a month, to be exact! That’s how much the 43-year-old talent manager has requested in court papers — $301,000 in spousal support and $135,000 in child support for their two children, River, 6, and Remington, 4, even though Kelly has primary physical custody. Brandon, whose net worth is estimated to be $10 million, is also asking Kelly for $2 million to cover his attorney’s fees. Needless to say, the divorce has gotten ugly. “Kelly and Brandon can’t even stand to be around each other,” a source tells In Touch . “Things were amicable enough at the beginning, but now it’s an all-out war between them.” Kelly, 38, feels “completely broken” by her divorce, says the source On the Nov.…