USB ports do not work. Can I buy an adaptor to turn one of the other ports into a USB?

I have an 18 month old Toshiba Satellite notebook. It’s fine and does what I need however I was using a wireless network and over used the USB ports. Now none of them work. I’m fairly sure it’s the ports as I’ve tried replacing the software, and the peripherals work OK on other computers. I don’t want to spend an awful lot of money so what’s the cheapest way to fix it? Can I buy an adaptor to turn one of the other ports into a USB?
My laptop is an EA60-155, Model PSA67E-00300C8J.

I’m not familiar with this model, but most likely USB ports are a part of the system board and to fix the problem you’ll have to take apart the laptop and replace USB ports (if you can find them). Most laptop repair shops will recommend replacing the entire system board. You are right, that’s very expensive.
Fortunately there is another solution and it’s much cheaper. All laptops have at least one PCMCIA CardBus slot, very often called simply laptop PC card slot.
If you need USB ports, you can buy a card called “USB 2 PCMCIA Laptop Card”. You plug this card into a PC slot on your laptop and get 2 or 4 USB ports; it depends on the model of your card. Make sure that this card supports USB2.0 standard, it’s 40 times faster then USB1.1.
For wireless networking you can buy a wireless laptop PCMCIA card. This card also plugs into a PC slot on your laptop. Make sure that your new wireless card supports 802.11b (11Mbps) and 802.11g (54Mbps) standards.