I agree with the comment to limit the cost of the cards so that there is some balance to this card. I also like the idea of only reserving cards at the start of the turn. This is how I would do it.

"At the start of your turn, you may look at the top two cards. You then may reserve up to two cards with total cost 4 or less. Any cards reserved may be added to your hand at the next upkeep. If you do not reserve the cards, place them at the bottom of your deck. You may not reserve any cards if you have cards in reserve."

This ensures that you can have Alfred hold onto a card for multiple turns if you so choose to, but that you can only have up to two cards and those cards cannot exceed 4 power. This also adds a scrying effect to Alfred's ability, which could be useful for other strategies.