You need an amplifier.
Tell us what you know about the subs and we can help you find a suitable amp. Model numbers, pictures, etc. are all useful information.
Here are some amps. Review these, and that will help you identify what is important to you / what your constraints are for the amp.
Behringer iNuke 3000: Lots of power for the money. Has a loud fan in stock form, but you can swap in a quieter computer fan. Very lightweight. You will need some inexpensive but uncommon plugs to connect it: RCA-to-XLR for the inputs, and Speakon outputs. Ugly -- silver with a bunch of orange lights. DIY audio people think this is "small and inexpensive", but I suspect that non-enthusiasts would see it as "large and expensive". It's ~$300.
Crown XLS-1000: Quiet, even though it has a fan. Has the common RCA inputs and binding post outputs. Less power for the money than Behringer, but also more convenient for home users, and Crown has a better reputation as a brand. There are more expensive models with more power if you need it. Still ugly in a home setting, but less ugly than the iNuke. Also light, small, and relatively cheap by DIY audio nut standards, but large and expensive by non-enthusiast standards.
(There are similar models for the amps above with more power, if needed.)
Behringer EP4000: This is a really popular sub amp. Lots of power for the money. Big, heavy, and has a loud fan. Was on sale recently for $275, but still a reasonable deal at the current price, though I would get one of the amps above instead since they are easier to work with (weight, fan noise).
Behringer A500: Less power than the first two. Silent, since it has no fan. Heaver than the first two, but still not that heavy. Has common RCA inputs and binding post outputs.
Dayton DTA-100a: This is not normally used as a sub amp (it isn't "popular" like the ones above), but it could work as one, and it is small, silent, and relatively cheap. I'm not sure it has enough power for your application, but it may be worth consideration.
(I own all of these amps, or a variation: iNuke 3000DSP bi-amp center, Crown XLS-1500 sub, EP4000 unused, A500 garage sub, DTA-100 bedroom system)