Go to your local music store and rent a serious synth and/or sampler for a couple of days.
or:
If you have no experience of programming, it may be cheaper to find a local heavyweight keyboard player and have him/her do the programming and/or recording for you. If you're seriously short of $$$, you may be able to work out a barter system type deal such as painting the outside of the house, yard work, etc in exchange for ...?
If you plan on doing more recording using strings/horns in the future, it may be worth your while to spend the money now so that you will be familiar with the synth down the road.
Have fun!
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