You will only be entitled to Carers allowance if the person you care for receives one of the higher rates of PIP. If you are intending to work, there are some pretty complicated rules about earnings cut off points (if memory serves, its about £100 per week) and you would need to get expert advice on this.
Going back to PIP, if it's your daughter that you are claiming for, why would she need mobility, unless she has other issues? The care component yes, but I wouldn't have thought mobility would be necessary?