High Frequency, High Power Amplification
5 MHz is not that much, and neither is 1A.

For example, LTC1206 can amplify at up to 60MHz. Its output current is "0.25A to 1.2A".

OPA564 is up to 1.5A, 17MHz amplifier. Its gain-bandwidth product is a bit low (17MHz), so you will also want to add a regular, low-current preamplifier to it.