Emails sent are unreadable

We are using the business edition 1.5.7 on joomla 1.7 website in arabic language. When the users register through hikashop (during checkout), the email that is sent to finish the account activation is unreadable as this example:
ุ�s…ุฑุญุจุง
sดู�ุฑุง ู�ุชุณุฌู�ู� ู�ู�
ู�ุฌุจ ุชู�ุดู�ุท ุญุณุงุจู� ู…ู� ุฎู�ุงู� ุงู�ู�ู�ุฑ ุนู�ู� ุงู�ุฑุงุจุท ุฃุฏู�ุงู�ุ� ู�ุณู�ู� ุชู�ู�ู� ู�ุงุฏุฑุฉ ุนู�ู� ู…ู�ุงุตู�ุฉ ุทู�ุจู�

Same thing with the email sent to the customer with the order creation notification:
ุ�s…ุฑุญุจุง

s�ู� sนู�ู�s�ู� s�ุญู� ุณุนุฏุงุก ู�ุชุฃู�ู�ุฏ ุฅู�ุดุงุก ุงู�ุฃู…ุฑ ุฑู�ู…

ู…ู�ุฌุฒ ุงู�ู�ุธุงู… ุงู�ุฎุงุต ุจู�
ุงู�ุงุณู… ุณุนุฑ ุงู�ู�ุญุฏุฉ ุงู�ู�ู…ู�ุฉ ุงู�ู…ุฌู…ู�ุน
ุฃุณุงุณู�ุงุช ุงู�ุชุนู�ู�ู… ุงู�ู…ุณู�ุญู� (2)
$0.57 1 $0.57
ุทุฑู� ุงู�ุงุณุชู�ุงู… : $1.50
ุงู�ู…ุฌู…ู�ุน ุงู�ู�ู�ุงุฆู� : $2.07

And the email titles have some arabic characters but are intermixed with unreadable characters as well like this question make and the letter "s" as follows:
s�ي s�لنظام الآن s�ديك عدد

As for the emails sent to the hikashop admin when an order is created, confirmed or with payment info, the arabic characters appear but they do not make any sense like:
النظام الآن

كان هذا الإشعار ل ? النظام على الموقع
يمكنك الوصول إلى تفاصيل النظام مباشرة من خلال النقر على الرابط التالي بعد تسجيل الدخول في نهاية الخاص بك مرة أخرى

Can you please advice, how to correct this problem.

All emails sent from the website not through Hikashop (through RSForm Pro or joomla user registration email) are fine with no problems. I checked the setting in Hikashop email tab of the configuration and it is set to Charset to UTF8 with encoding format Base 65. The problem is that some of the emails come with this unreadable characters and some come with arabic characters but with the wrong translation. Also, the s% that is in the language file, gets printed as is instead of picking up the field for its value.

I also noticed that when I edited the language file from inside Hikashop, emails sent to the buyers are unreadable but emails sent to hikashop admin are readable but with the %s problem. In this same case, when I open the language file under /language/ar-AA/ar-AA.com_hikashop.ini with my own editor, all arabic characters are unreadable. Now, when I took a copy of the content of the arabic language file from inside Hikashop and replaced what is in ar-AA.com_hikashop.ini, emails sent to the buyers had arabic characters with the s% problem but emails sent to Hikashop admin were unreadable. It seems that it is either/or. Also, I noticed that the arabic that appears is flipped in-spite that the alignment is correct for example: it appears as ,s% hello rather than hello s%. Keeping in mind that arabic language is read from right to left.

Hope this information helps in figuring out a solution to this problem.

This is how I got the translation file to start. I downloaded it from your website.

OK. Great! Half the problem is solved now. With the new language file that I downloaded, all emails sent are in proper arabic character. However, the order of words still read from left to right instead of right to left (although sentences are aligned to the right). For example:

مرحبا testing family،

should be:
،testing family مرحبا
(which is the the translation for Hello testing family,)

Also, the fields (like for customer's name, order number, ...etc) are filled properly with their corresponding values in the emails sent to the buyers however, they are do not show in the emails sent to the admin emails thus making the arabic sentence hard to understand. so for example:
كان هذا الإشعار ل ? النظام على الموقع

should have been:
This notification was for the order xxx on the website xxxx.

Where you see the ? in the arabic sentence is where the order number should have been printed and at the end of the sentence, the link to the website should have shown.

Ok. Thanks for all your help. I will update the language file.