Why Fight if You Don't Have To?
You have this wide fast river between you and the footborne unit that's attacking, so why fight?
If the Army is coming to the rescue in 24 hours all you really need to do is delay the Moronian's advance. You can do this by committing almost no forces of your own. The US Army division that is coming to your rescue will engage and most likely destroy or disperse the Moronians with long range fires before any ground maneuver units arrive. Tac air, attack helos, MLRS and 155mm artillery will have them under fire early. If the division is only 24 hours out, there is most likely an LRSU detachment already in the area with eyes on the enemy. All you need to do is bottle them up at the bridge and wait. The engineer battalion organic to the divison base will have enough bridge to completely cross the river if necessary, replacing one span of the existing bridge won't slow the counter attack down by much.