It's never good to say outright or even to imply that you want the sitting president to be assassinated. I think she definitely will be getting a visit from the Secret Service for that one and they'd be within their rights to put her in jail for it.
Freedom of speech doesn't apply to that. Like him or hate him, Obama is the sitting president and you can't say those kinds of things.
Plus, she's not thinking this through very well. If he were to be assassinated, he'd be made into a martyr figure for progressivism/communism by the left wing media outlets and then most of his evil agenda would get passed much more easily. Also she's being selfish. A lot of us don't like Obama as a person but why does she want to punish his young daughters by taking their father away? That's really cruel. They may have been raised to be left wing, but they could choose differently later in their lives, and to punish them for their parent's politics would be wrong.
I think we should want Obama out of office legally. Fight him politically, get him impeached, oppose his evil agenda in every possible legal way, but don't go after him physically. It would only polarize the country further and get conservatism a lot further away from its goals.