Outdoor passive sub help please...

Ok need a little help here. I'm trying to get a decent outdoor speaker setup going and here's what I got, just need help with passive sub. I have a Sony str-510 receiver that is a 5.1, with 100w per channel, two Yamaha NS-AW570 (6ohm) speakers, two TIC omni GS5 speakers (8ohm). I would be totally cool with this around my pool, but got a great deal on a brand new rock passive subwoofer for $40 that I could not pass up. Its model is NX-PRO1000 (8ohm), very nice looking 10" rock sub that I would like to utilize. I'm not sure how to wire it up with the receiver I have, and if I do is it even worth it with the receiver I got? I don't really want to shell out another $150-200 on a mono amp if I don't have to.
What I believe the manual says is to wire the subwoofer from the receiver in parallel to the sub, out to two of smaller speakers. The idea is the sub will take the lows and the mids and highs will go to the omnis, or yamahas.
Any help, suggestions, drawings?


Thanks for looking

Victor or anyone else that can help....
I found a 2 year old used, working Sherwood Receiver 2.1 model RD-7103 for $30 on craigslist which is 6ohm at 100w per channel.
Will this work out well for my passive subwoofer a whole lot better than just using the HK to power all? I ordered a HK 3390 to power 2 other pairs of outdoor speakers and then use the sub out on the HK to the Sherwood?
Thanks

Victor,
I hooked up the two receivers like you said and it sounds awesome!
I have a question though, the subwoofer runs fine with just one rca cable connected, the red from one receiver to the next or vice versa. So I was wondering if I should just get a single jack subwoofer cable since I'm actually only running one rca cable to the next. I'm not sure if it would make it sound sub sound even cleaner with a mono subwoofer rca cable compared to the double male red, white rca cable. Basically I'm just running the red from one the receive to the next and the white cable just dangles. Any thoughts?