Eighty artefacts from the hoard are going on show in Stoke next month
The leaders of all three main political parties have backed a campaign to keep the Staffordshire Hoard in the West Midlands.
Gordon Brown, David Cameron and Nick Clegg all said the find of 1,500 pieces of Anglo-Saxon gold were important to the area and should stay there.
The Art Fund's campaign has until 17 April to raise the £3.3m needed to buy the hoard and keep it in the region.
It has so far raised £553,500 towards that amount.
The campaign was launched on 13 January by celebrity historian Dr David Starkey.
The Art Fund donated £300,000 and Birmingham and Stoke-on-Trent's city councils each gave £100,000.
A further £53,500 has been raised through public donations so far.
The Art Fund said it feared the collection could otherwise be bought by private collectors and split up.
Mr Brown said the hoard was a "wonderful example of our hidden heritage".
He added: "I really hope that the money can be raised to keep it where it belongs - in the English midlands, as a source of wonder, knowledge and delight for young and old for ever."
More than 80 artefacts from the hoard will go on show at Stoke-on-Trent's Potteries Museum and Art Gallery next month.
Dr Stephen Deuchar, of the Art Fund, said: "It's clear from the support shown by our party political leaders that this is a campaign that really does matter."
He said £553,000 was an "impressive start" but said there was a "very long way" to go before they reached their target.