When you say,
bq). ...design a rf receiver that can activate...
Do you mean that the rf transmitter and loud siren already exist and you just need the receiver?
If so, describe the transmitter (frequency, output power, what does it transmit, etc.) and describe the loud siren (input voltage/current/power/impedance/etc)?
BUt then you say:
bq). Range as long as possible
Which implies control over the range, so that suggests that your wording is misleading and you want the whole package -- in which case, I need more than "Range as long as possible." I can give you range to the Moon (and beyond), if you can pay for it, so I need some concrete numbers or at least the scenario it will be used in (distance/terrain/indoors/outdoors/typical weather/etc.)
When you say:
bq). i also need a settable output that will switch after 15 seconds
Do you mean "switch _off_" after 15 seconds, and if so, switch what off? The siren? (I get that it might be obvious, but your language is vague and I don't like to assume).
When you say:
bq). pp3 powered
do you mean powering the Receiver, the Transmitter, the Loud Siren, all of the above?
Also, how long would you want it/them to last on that 9V battery? Is there potential for a solar panel, or wind generator, other such sustaining power source (i.e. that could charge that battery when its/they not in use)?
Also, how often do you foresee this device being used (i.e. will it be sitting idle most of the time, will it see infrequent periods of heavy use, or is it more like once in a rare while)?
