saab: "close to" is a relative term. If you want to be near both properties, then I assume you'd want to be in between, which would put you somewhere on the I-4 route between the Downtown Disney exit and SeaWorld. I'd suggest loggin on to Expedia.com, which is showing some rates within your price range for some decent properties -- Clarion Hotel Universal, the Wyndham Orlando Resort, and the HoJo Plaza Hotel and Suites. Truth be told, however, if you can factor in an extra $20 a day, you could even stay on property at one of the Disney value resorts.
Good luck, and have a great vacation.