I would use what Anton said int count = SearchContext.CurrentSearchResults.Count;
I am not 100% positive on this, but I thought if you used pagination that this count wouldn't be 100% accurate.
If you need an example of setting up search paramters, you can just look in the search results web part you are using:
SearchParameters parameters = new SearchParameters()
{
SearchFor = searchCondition,
SearchSort = PredictiveSearchSort,
Path = PredictiveSearchPath,
ClassNames = PredictiveSearchDocumentTypes,
CurrentCulture = PredictiveSearchCultureCode,
DefaultCulture = CultureHelper.GetDefaultCultureCode(SiteContext.CurrentSiteName),
CombineWithDefaultCulture = PredictiveSearchCombineWithDefaultCulture,
CheckPermissions = PredictiveSearchCheckPermissions,
SearchInAttachments = false,
User = MembershipContext.AuthenticatedUser,
SearchIndexes = PredictiveSearchIndexes,
StartingPosition = 0,
DisplayResults = PredictiveSearchMaxResults,
NumberOfProcessedResults = 100 > PredictiveSearchMaxResults ? PredictiveSearchMaxResults : 100,
NumberOfResults = 0,
AttachmentWhere = null,
AttachmentOrderBy = null,
BlockFieldOnlySearch = PredictiveSearchBlockFieldOnlySearch,
};