OK, well youve got the idea on how to get yourself a decent sounding system....so thats good
Its going to be a little hard to find an amp that will run your two subwoofers and the front splits (like camstatic above mentioned about the amp being 2 ohm stable when bridged). So you have three options, depending on how much money your willing to spend.
1. Buy a "monoblock" amplifier (these are made to run subwoofer/s) to power your subwoofers. Ive provided some links below as examples of what you should be looking at. You dont have to go with those exact models / brands, but its just to give you an idea. Something with 300-500wrms at 2 ohm impedance will be ideal. Then youve got your front speakers (splits), in this cheaper option im suggesting to run these off the head-unit untill you can afford to buy a second amplifier to power the splits to their full potential. They will work fine off the head-unit, just wont play as loud and you wont be able to filter out the low bass frequencies that the sub plays (its called a high pass filter) unless your head-unit has a HPF. Which model is the JVC head-unit?
2. Buy a "4 channel" amplifier, power the two subwoofers off the rear two channels (if its 2 ohm stable bridged, then wire the subs together then connect them to the bridged channels, if its not 2 ohm stable when bridged, you'll need to connect each subwoofer to a channel). Then you can power the front splits off the other 2 channels of the amp. This option really dosent provide you with enough power to the subs, but it'll still work and you'll be able to get away with it, just wont sound as good as two amps (one for subs, the other for front speakers).
3. But the same monoblock ive suggested in the first option, but buy a second "2 channel" amplifier for the front speakers.
Heres some links below for amplifiers and front speakers, but i do suggest to get into a car audio store and have a listen to as many types of splits as possible, you should find a set or even two that stand out from the rest.
6-6.5" Splits:
Pioneer Entry Level:
Ryda Car Audio - Pioneer Car Audio TS-C1602 Car Speakers($130.85)
JVC Entry Level:
Ryda Car Audio - JVC Car Audio CS-FS60 Component Speakers($130.95)
Sony:
Ryda Car Audio - Sony XSGTX1620S 6" Split Speakers($137.50)
Clarion:
Ryda Car Audio - Clarion Car Audio SRP1620M 6" Split System($175.95)
Sounstream:
Ryda Car Audio -Soundstream PCC.6N Picasso - 6.5" Speaker($223.75)
Alpine Type S:
Alpine Electronics of Australia
Alpine Type R:
Alpine Electronics of Australia
There are a few higher end brands out there, but they also come with the prictag...most are over $400. Brands like Focal, MB Quart, Boston Acoustics are stand-outs.
4ch. Amplifiers (for option 2):
Jaycar Response:
Response Car Amp 4x100WRMS - Jaycar Electronics
JL Audio:
Ryda Car Audio-JL Audio G4500 G Series 4 Channel Amplifier ($454.55)
Clarion:
Ryda Car Audio - Clarion Car Audio APX490M 4 Channel Amplifier($387.95)
Theres a few other brands out there, and for amplifiers brand dosent really make a difference to sound, only looks, power output and ofcourse price are the main things to worry about. A model with 80-150wrms per channel is ideal for your situation.
"Monoblock" Amplifiers:
JBL 300wrms:
Ryda Car Audio - JBL GTO301.1 Mono Subwoofer Amplifier($242.95)
Kenwood 500wrms:
Ryda Car Audio - Kenwood Car Audio KAC-8104D Car Amplifier($192.45)
Pioneer 400wrms:
Ryda Car Audio - Pioneer Car Audio GM-D7400M Car Amplifier($279.95)
Jaycar Response 600wrms:
Response 1000WRMS Linkable Car Monoblock Amplifier - Jaycar Electronics
Once again theres a few other brands out there, but price and power output are the main differences. Basically you want one with as much power as possible for your budget, even though you might not use all the power the amp can make, it wont have to work as hard to push your subs to their full potential and if you catch the bug and decide the upgrade later down the track it always handy to have the amplifier ready for the job
You'll also need to factor in wiring / installation costs (if you dont want to do it yourself). Wiring for one amp will cost around $80.00, whereas for two, maybe $150 - $180. Installation could range from $200 to $400 depending on what components you'll need to be installed.
Sorry for the long post, but hopefully it gives you an idea on which way to go