I am not offering 以上です as a proper translation, as I am not familiar with Japanese legalese for affidavits.
However, the English phrase has no significant meaning, it is usually the last sentence of an affidavit, and the literal translation to normal English is: "The affiant says not further".
Similar to 以上です at the end of a letter.
Please read the article at the URL provided below, it explains more about this phrase. It may help you find the Japanese equivalent, if any. (The article suggests to ignore this phrase.)

法律英語特有の古めかしいいいかたですが、要するに「以上です」というようなことで他のひとの答と本質的には同じですが、もう少し理解を助けるために付け加えますと：

「宣誓口述人はこれ以上いうことは何もありません（付け加えることは何もありません）。」
ということになると思います。
affiant　宣誓口述人
further これ以上
sayeth　いう
naught　何もない

ご参考までに。

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Note added at 8 hrs 7 mins (2005-06-25 23:19:48 GMT)
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つまり宣誓口述人の宣誓口述の最後の締めくくりの言葉です。

ポイントの対象外の答えです。
ご参考まで。
References
Barbara Child, Drafting Legal Documents: Principles and Practices 79 (2d ed. 1992): ‘‘There is no need [in an affidavit] to add the gratuitous traditional tagline of legalese: Further affiant sayeth naught.’’

Bryan A. Garner, A Dictionary of Modern Legal Usage 378 (2d ed. 1995): ‘‘American lawyers frequently end affidavits with some variation of this sentence: ‘Further affiant sayeth not.’ This sentence gives rise to three stylistic dilemmas: first, is it sayeth or saith; second, is it not or naught; and third, is the sentence necessary at all?...Among American lawyers who use the phrase, sayeth predominates; among American lawyers who rightly pride themselves on their style, the phrase does not appear at all....The predominant form [between not and naught] is Further affiant sayeth not. But this is nonsense, because it is literally translatable as, ‘The affiant says not further’....The form with naught, by contrast, makes literal sense....[But t]he best choice, stylistically speaking, is to use these phrases not.’’

Thomas R. Haggard, Legal Drafting: Process, Techniques, and Exercises 320 (2003): ‘‘Another form of legalese consists of antique phrases like...Further affiant [or deponent] sayeth not.’’

David Mellinkoff, Legal Writing: Sense and Nonsense 134 (1982): ‘‘Further affiant sayeth [or saith] not―often the last line of an affidavit. Adds nothing to sense. Delete and stop.’’

Wayne Schiess, What Plain English Really Is, 9 Scribes J. Legal Writing 43, 71 (2003ﾐ2004) (forthcoming): ‘‘This is the profession in which no lawyer would speak to a jury in complex and jargon-filled legalese, but if asked to write an affidavit for someone on that jury, the same lawyer wouldn’t hesitate to use the phrase Further affiant sayeth naught.’’
最初のURLから引用。

The judge has been unnecessarily harsh on the petitioner in
this matter an it has appeared to at least two other witnesses to
her conduct that she has acted in a prejudicial fashion toward
the petitioner. (Exhibits attached). Further the court has
imposed such impossible financial burdens on the petitioner
Accordingly, affiant moves and prays that the Honorable Joyce
Steinhardt be disqualified from further proceedings in this
matter.

FURTHER AFFIANT SAYETH NAUGHT.

This is the 22nd. day of July, 1987.
VERIFICATION AND AFFIDAVIT
２番目のURLから引用。